BMW tuning specialists Hartge Engineering are very familiar with the first rule of hot rod builders everywhere - there's no replacement for displacement. That's exactly the principle they applied to BMW's European entry-level model, the 1 Series, when they gave it an engine transplant from the M5.
The resulting H1 was put through its paces by the crew over at World Car Fans, and as you might expect, a five-liter, 450 hp V8 powerplant gives a 3,185 lb car fairly impressive performance - 0-60 mph in 4.6 seconds, with a top speed of 188 mph. Even with the big V8 jammed into the RWD hatchback's engine bay, the front/rear weight distribution is reported as a surprisingly well-balanced 52/48 percent, giving the car handling to match (if not actually control) its massive power. (Follow the link for the full road test.)
The usual suspension upgrades keep the 19-inch wheels in contact with the pavement, and a fairly understated bodykit helps the aero and cooling without succumbing to the boy-racer look.
The price for the pocket rocket is - wait for it - about $128,000. Which brings to mind another hot rodding aphorism - "Speed costs money. How fast do you want to go?"
[Sources: World Car Fans, Hartge]