The R300 / 360R is a standard Duratec with 175bhp The R400 / 420R kit adds cams, injectors and ECU at £2300 and has 210bhp and an 8000 rev limit. The 220bhp at £5300 kit adds roller barrels, cams and injectors. The roller barrels on their own cost £3700 and will get you to 195bhp Above this you need pistons, rods, head work etc. etc. The 210bhp is the best addition cost wise, the roller barrels add character with more noise and 10bhp to the R400 spec but cost a hell of a lot.