Called the 335is, this short-lived 3-series version featured a tuned N54 making 320 hp and 332 lb-ft, with a special overboost feature that temporarily raised the torque output to 370 lb-ft.

The N54 became the stuff of legend on the BMW tuning scene. Its successor, the N55, is less of an out-and-out powerhouse but it too has some serious modding potential. Whichever version of the BMW ...