as above really dont know what to go for would like to hear your opinions on both engines trying to keep budget down to a min though really thanks adam

Well a while back I had an S-reg R1 and the engine was truely brilliant.

Probably depends on too many factors to give a definite answer. The zx12 is around 30bhp more powerful and has around 30lb/ft torque more (please someone correct me if wrong as I aint double checked that). But......you pay a bit of a premium for that. In terms of $ you need to figure out if either would need dry sump (prob. track only).

I personally went for the zx12, mainly cos I'm not exactly light weight and wanted something that could handle my weight (up to 16-17 stone in training) and passengers. I guess the overall expected weight of the car could be a deciding factor.

If in doubt, apply the Tim "the toolman" Taylor, principle of "more power".

Hi, Depending on year the R1 wont need a dry sump(>04 i believe) and instead needs just the baffle so keeps the cost down. Also seems to be a lot of R1 engine kit cars out there so theres always some one on hand to help you out if you get in trouble with the install.
Adam