When someone pulls up in front of your house and asks you if you want to drive a heavily modified 542 HP BMW 5-Series, there's really only one right response: "I hope I can find some pants."

Leg-tubes of oppression found and donned, I walked outside and was greeted by the imposing white bulk of the BMW. It's a car with a lot of presence, and the gleaming white paint and black aluminum wheels and subtle carbon fiber details imply with a raised eyebrow that this isn't a , which is already a great sleeper.

Jason Bourne. Under his white-collar appearance and cool demeanor is a wild animal that — at the…

, for those of you not aware, is a tuning company that specializes in BMWs. They sell their upgrades in "stages," starting with engine software reprogramming, through suspension upgrades, exhaust systems, all the way up to a twin-turbo upgrade.

Each Dinan upgrade adds a "point" or a few points to your cars, um, score. When you hit a certain number, and only then (I think it's a Dinan score of 10) can your BMW wear the "DINAN" badge.

They take this really seriously, going so far as to shut down factories in China that were manufacturing the letters D, I, N, and A in a particularily familiar typeface. The car I was brought to drive had all the letters on the back, and they looked to be in the right order, too. No BMW NIDANs for me.

The one I got to drive had pretty much everything, and is described as a sort of sleeper. From the outside, it looks like a fairly normal 550i, inside it has even more luxurious touches than a stock one (and ahead of the M5, too), but the true nature of this thing is an absolute beast. It's like putting a silk jacket on a carefully shaved Sasquatch and sending him to finishing school. It'll pass at parties, but for fuck's sake, don't get him mad. Let him double-dip.

So, there's 542 HP, 587 lb-ft of torque, and the torque and power are felt all across the power band, with the biggest gains in both torque and HP coming in around 6500 RPM. My favorite upgrade, though, is a front tower strut brace that also acts as the cold air intake. It's a hollow carbon-fiber piece, and I'd never seen that done before. It's clever in the same way my Beetle's windshield washer is powered by the spare tire, but much more, um, fast.

So, what's this thing like to drive? Thanks to the affable JK who brought the car over, I was encouraged to take it through the twisty roads in Griffith Park and really see what it could do, within, of course, the rough limits of morality and the law.

It's a beast. A cultured beast, like I said, but underneath that layer of refinement it's a terrifying machine. It's like sitting in a comfortable, leather-slathered machine built with the sole purpose of separating you from your license. It's manageable in traffic without much trouble, and it's not really taxing to drive, but the throttle response is so immediate and potent and intoxicating it's almost impossible not to really give it the kraut every chance you get.

On the twisty canyon roads, it's impressive, especially when you consider the size and weight of the car. It has amazing grip, much less body lean than I'd have assumed, and the steering feel, while clearly heavily assisted, feels quick and direct. It's genuinely fun, and when you get that right combination of corner and speed, really rewarding.

But also incredibly frustrating. It's my same complaint with almost any of these incredibly fast, well-engineered cars: unless you regularly track this thing, there's no way you're getting a tenth of what this car can do. So, I'm always left conflicted after driving cars like these: they're incredible, but I know if I had one my inadequate self-control would end up with me getting the thing impounded. And when I'd be sitting with one in traffic I'd feel like I was doing the machine a great injustice.

There's also a more philosophic issue I have with cars like this: they're just not me. I respect the hell out of them, and love driving them, but as far as owning one, the imposing character and absolute-best-of-everything persona just isn't what I'm about, and I'd always feel like an imposter driving one of these. I'm an imperfect man with imperfect tastes, and that's just something I've grown to accept.

Still, if you had the resources, track access, and personal restraint beyond me — not exactly high bars for any of those — a DINAN-massaged BMW is a pretty fantastic thing.