well my car was knackered to start with, my head gasket had gone, oil was leakin, bearings needed changing and cam belt, my engine wouldnt even start so i couldnt even jus sell it lol all that was gonna cost 550 including labour from a relative so that was a good price BUT its not like i wanted to spend that amount in the first place as i only brought it for £1300, but luckly i had 600 saved, i spoke to him an said look if im payin this amount of money can u replace sumfin thats gonna make it faster for me, so he replaced the cams an exaust, the cams were 200 includin the labour, an i think cams are pretty expensive, but most people have all said u need the sports exaust to feel the full power... theres defo an increase, but uno, for all i kno it could jus be that fat exaust of mine lol! i havent got a clue when it comes to tuning, its my first car ive started to modifiy, u would need to ask other guys on here who really kno wot each component does, im still learning. sometiumes we make mistakes, waste money wot we didnt need to but we learn from it, uno wot i mean