If you’re passionate about your ride, chances are good it isn’t stock. The most afflicted among you have probably spent as much on aftermarket performance as the car cost to buy, while others are happy to change out a gearshift knob or add a deck lid spoiler.

BMW is well aware of how much Americans spend to personalize their cars, so the Bavarian automaker is introducing a line of M Performance accessories for the new 2012 BMW 3 Series sedan, as well as 2011 and later 5 Series sedans. Some items, like the M Performance steering wheel, the Brembo big brake kit or the high-flow exhaust system, are functional and may actually increase your car’s performance.

Other items, like the carbon fiber mirror caps or the carbon fiber and Alcantara interior kit, are cosmetic only. Some accessories fall into the gray area in between cosmetic and functional; the 20-inch forged wheels, for example, save just 2.2 pounds per corner, which really won’t add much of a performance gain. We suspect there are plenty of aftermarket wheels available that cost less money and save significantly more weight.

That’s really not what the M Performance parts program is about. Sure, you can spend your money on aftermarket parts, but they won’t be backed by a BMW warranty or installed by a BMW dealer (in most cases, anyway). If you’re more concerned with convenience and a warranty than outright gains, the BMW M Performance parts may be worth looking into, and your dealer can give you complete details on availability and pricing.

Just promise us that you’ll skip over the hideous vinyl stripe that’s part of the M Performance collection, okay?