Standard RST's are 'ok' but never beat a cooper S with one!

you need firstly:

Mongoose/Magnex exhaust
chip (to remove boost limit)
front mount IC (so you can raise the boost safely with the chip and not have sky high charge temps, the std IC is 'ok' for 13psi any more and it struggles)
then a high lift cam
keep the std airbox and cut the front off where the circular hole is on the top half of the lid!
with all that you'd be looking at around 180-190bhp on 13-14psi setup correctly on a healthy engine.
After that your into hybrid/bigger turbos and lower compression pistons but if the engine is coming apart i'd go for a ZVH or Zetec Turbo!


Cooper S's (the old ones) have 163bhp, 0-60 in 7.4 and a 135 top end
nothing rapid, get it chipped, exhaust, cam and a bigger IC and you'll have him