I agree with big g,ive been running a 5.5 in my cars for the last two years and not improved one bit really. So,as I decided to buy myself an x2c I thought I'd try a milder motor,7.5. Ive since got more confident in driving and far more consistent with my lap times. So ive decided to give it a go in my fs2 for the next round at worksop and hopefully I can do the same in 4wd as I have in 2wd. SPEED IS NOT EVERYTHING. (only took me two years to find out).