Originally Posted by Shoeshear

ISF is pretty quick, supposed to be an M3 competitor at the time. Almost certainly faster than a Z, probably drives like a bigger car though (curb wt around 3800lbs). It sounds pretty awesome though, it's got a Japanese v8.

Also, why not the standard vette w/ z51? Plenty of power coming from a Z and can probably put a bigger cam and tune it if you want more juice. I'd say the Corvette is the bigger/powerful American version of the Z. I think the Z06 is overkill personally. My buddy has one and it's an absolute animal, but it's kinda lame not being able to row the gears much. I'm actually thinking about downsizing my motorcycle for the same problem lol. When 2nd tops out at 110 or something, there's no way to really enjoy the gearbox.

Also, have you considered a used 135i? Those can be boosted up to pretty crazy levels. My friend has one that's just shy of 500whp, just tune, intercooler, and exhaust.