well if you use the same place as me, turbo.jon and dave seaman have used its gonna be around 400 quid for the bottom end work,

i brought ross forged low comp pistons for mine £500 quid, arp bolt set £150, and alan at engine engineering done the rest, so i would set aside £1200, in all my complete engine,cam, turbo,grs, sets me in at 3k, but mine is estimated at 220bhp at 21psi of boost, you properly int as a lairy as driver as me, and u might want to keep yours more sensiable than mine.