The E30 M3 had the s14 motor which started out in life as S-4 2.3L NA motor producing 200bhp. The last version of the M3 was a 2.5L inline 4 that produced 240bhp. Add some heavy mods and a HUGE turbo and you get this:
More than 600bhp on a 4 cylinder engine... that's just insane!
