It never rains in Southern California.

Tell that to the pitter-patter currently spitting up all over the cracked asphalt in the San Gabriel Mountains outside of Los Angeles. I’ve come to this tangle of spidery mountain paths to test out a borrowed, restored Porsche worth $670,000.

It’s a once in a lifetime kind of thing. The car is special. Should I let a little rain stop me? How about a lot of rain?

A wise man might, considering that this Porsche was commissioned almost a year ago by a very fortunate owner who made a series of painstaking decisions about the exterior and interior colors, size of the engine, and types of leather. He’s waited patiently. Hasn’t even driven it. Yet he’s graciously agreed to let me take his unsullied beauty out for a spin. We’ve never met, but that’s how much he trusts and respects the company, Singer Vehicle Design, to whom he commissioned this unique car. (A salute to you, kind, anonymous sir!)

Meanwhile my co-driver and chaperone, Seamus Taaffe, cocks an eye to the wet sky and shrugs. Seamus is an Irishman who serves as Singer’s test driver, sometimes engineer, and all-around go-to man. "Well, let’s give it a go, shall we?"

That pretty much encapsulates the company’s worldview. Its modified cars are meant to be driven, not molder in a showroom.

And so we do. I fire up the 4.0-liter flat-six engine, with almost 400 horsepower, shove down the tall clutch, put it into first, and head out. May the saints of these slippery roads be with me.

Officially, this car is a Porsche 911 Reimagined by Singer. A mouthful, to be sure, meant to forbear any legal Sturm und Drang from Porsche itself. Singer says it "restores and modifies existing Porsche automobiles … [and] does not manufacture or sell automobiles." Which doesn’t really explain what a 911 modified by Singer is or why its services command such crazy sums.

The company has been around since 2008 and thus far has 110 customer orders, with 42 restorations completed. Singer restores and modifies only one model, the 964-era 911. Yet it has caused one hell of a stir, jellying the jaded reserve of hardcore automotive journalists and hard-nose collectors alike. In the calcified realm of vintage automobiles, Singer is akin to a tech unicorn.

Fifty-year-old Rob Dickinson is the Zuckerberg of the operation, a British transplant to Los Angeles and a former rock singer known for his complicated relationship with perfection. "I’ve been burdened with a healthy dose of obsessive compulsive disorder, but I don’t think this car would exist without it," he says. "I’ve literally been obsessed with the Porsche 911 since the age of five." He describes his vision as a "Frankenstein," which seems terribly unkind, because the result will stop your heart. A 911 that has been modified by Singer is a bang-up of old and new, the 911 that exists in our minds but never existed in reality.

Dickinson describes it thusly: "Our goal is to celebrate Porsche’s heritage using the benefit of post-modern insights, new techniques, and new materials. We repatriate the finest air-cooled 911 chassis while incorporating the purest 911 bodywork from the 1960s. Then we turn the volume up on certain aspects. Our goal is for the owner to end up with the ultimate 911."

A 911 with Singer’s services is one of the most beautiful Porsches you’ve ever seen, an artful mélange of design. But unlike a very old Porsche, the promise is that it will start every time you turn the key, and it will outrun many modern sports cars. All the while retaining the anima and spirit of a classic, without the deadening encumberments of electronics like traction or stability controls.

It’s Coke Classic, only naturally sugar-free and full of vitamins. Led Zeppelin on tour one more time, with John Bonham at the drums. Kurosawa directing the third installment of Kill Bill.

It’s the impossible dream.

A Porsche 911 restored by Singer starts with the chassis and body of a classic 964 911, an air-cooled model built from 1989 to 1994. This generation retains the general size and proportions of the first 911s, but has engineering advancements that make it less squirrelly and better to drive. For instance, its coil-sprung suspensions did away with the clunky torsion bars of the previous generation.

Prices for Singer’s services start at $395,000 and average around a half million, depending on the owner’s preferences. That doesn’t include the "donor" car, which Singer doesn’t actually buy, but which they can help clients find if necessary.

The car is stripped and taken down to bare metal, rust blasted off, then it is sealed and strengthened, and fitted with custom bodywork of carbon fiber, including the bumpers, hood, and fenders. This makes the 911 lighter and stiffer. These structural changes also resculpt the silhouette so that it looks more like the earliest, coveted "Butzi" generation 911. (The one designed by Ferdinand Alexander Porsche himself, who died in 2012.) The result is lovely, with swelled rear hips and upright, round headlights.

And so begins the world of owner choice. Engines range from a 3.6-liter six (270 horsepower), to a 3.8-liter (360 hp), to a new and vaunted 4.0-liter (390 hp). (Note that Porsche itself only sells a 4.0-liter on the peerless 911 GT3 RS.) All engines are handbuilt by a California-based outfit, Ed Pink Racing Engines.

Singer has only offered manual transmissions, five- or six-speeds, with an optional limited-slip differential. Owners can deep dive into all types of brakes and adjustable suspensions and various engineering esoterica. Suffice it to say the modifications and restoration services can be as hardcore as desired. And of course, there are the bazillion color combinations and interior choices. Singer uses some 150 parts suppliers, many of them in California, where vintage restoration and fabrication companies are in abundance.

You’ve got to wonder if it’s all a rip-off. Half a million for a customization sounds insane. But the Singer employees are true believers. Obsession streams through the entire operation like a strain of bird flu. Talk to the guys working here and you’ll start to understand the level of obsession: the countless hours of thought, engineering and re-engineering, the quality and expense of the materials, and you begin to get it. They just can’t seem to help themselves. If an original Porsche part was plastic, and Dickinson or one of his minions think it really should have been forged of aluminum… guess what the end result is?

The lavender 911 I’m testing has the big brakes, sports seats, roll bar, and leather-swathed everything. The white leather weave which coats the interior of the doors, console, and seatbacks was done in Tuscany. But the most unique element is mechanical: it is Singer’s first-ever all-wheel-drive restoration.

AWD seems rather antithetical to Singer’s ethos, even though various Porsches have driven all four wheels for generations. Happily a simple, almost dumb kind of AWD was chosen, a system used in the 993 era car, utilizing a viscous coupling unit rather than a sophisticated electronic brain. It’s a part-time system, only powering the front axle when the rear wheels slip. Most of the time you’d never need it.

Except, perhaps, on a really curvy road on a day when it’s crapping down rain.

Singer Vehicle Design is located in LA’s Sun Valley neighborhood, housed in an inconspicuous shop in a row of ugly industrial buildings. Not the kind of place for a spirited drive. Seamus pulled out our 911 and navigated through town, promising "driving nirvana" a short distance away. Within minutes, we were headed up his normal proving ground, a stretch of asphalt up a craggy mountain with sharp, zig-zagging turns called Little Tujunga Canyon Road. "I know every inch of this road," he said. He drives every Singer-modified 911 here before it goes back to its owner. Shocks and suspension are calibrated until they perfectly match each vehicle. "They all drive a little different, are each a little bit unique," he trilled, a man obviously very happy with his job.

We switched seats, and I get one cautious, but dry drive up the mountainside. And then, goddamnit, the rain arrives. So we stop for photos, resolving to wait it out. It rains harder. "Big Tujunga Road is nearby, and it’s got less dangerous corners," Seamus says, as we both silently consider the specter of sliding off the pavement and leaving $670,000 worth of shiny parts trailing down a cliffside.

"Let’s go there," I agree. As I portage us to Big Tujunga, I acknowledge that there’s a certain poetry in the rain, seeing that we’re testing Singer’s first-ever 911 modification with all-wheel drive.

"See, nature is working for your story!" Seamus replies.

Hardly. Big Tujunga is also a great road, but there are small rivers flowing down it. I treat the gas pedal like I’m walking on eggshells, trying to learn the behavior of this car. The noticeable weight in the rear is familiar 911 stuff. The interior is intimate, but comfortable. The height of the clutch takes a bit of getting used to — but otherwise, if you can shift a manual-equipped Honda Civic, you’ll be fine. Unlike every other old car, the steering has no play whatsoever, and points you dead-center to the place your eyes are leading. I’d pay an easy $100 grand for that alone.

The 4.0-liter engine has gobs of power and makes a delightful roar from the rear, especially as you climb up through the revs. We roll down our windows before we pass through a small tunnel, as I downshift into second and race the engine. I repeat the process on the way back. Seamus and I, grown-ass men, giggle wildly both times.

Older Porsches are infamous for being tricky, even dangerous. This car has personality, all kinds of it, but it isn’t scary. Seamus says, "There are two kinds of powerful, old sports cars: one is a cat, the other is a dog. Cats want to secretly kill you, and dogs want to make you happy." If so, this car is a Golden Retriever.

And so I lose my fears, settling in, and the car settles too as I drive it harder. It’s fine toodling along, but the car likes gas. I occasionally feel the AWD engage as I come out of a slick corner. Helpful, but mostly unnecessary. I’d surely opt for a standard rear-wheel drive. Still, unlike most AWD cars, there’s no numbness in the steering wheel as the front end loads up. No dreadful understeer. In fact, this 911 turns into turns more eagerly than any I’ve ever driven. Light, fast, able.

There is no element of the car more robust than the other; the brakes, engine, and chassis are in happy harmony. It is deceptively simple. Luxury, as I define it, is an object or experience that has been so strenuously considered by its creators that the end user never has to think about or second guess those decisions. It gives you everything you want, but only what you really need.

That definition is the modified 911 in spades.

The rain has stopped, and the asphalt is sweating off the wet, transforming from dangerously drenched to only tricky-damp. My time with the Singer is coming to an end. I’ve been cautious and respectful, and now’s the time to be a bit less so. Seamus seems comfortable enough, so to hell with it.

I shift into third, step fully into the gas, and fly. It’s what the car was made for, after all.