seimens fit straight in!.63 aint cheap new around £350 i think bit if you can wait good second hand ones do turn up from £120-£160 i dont think standard 2wd inlet plenum will flow enough for 400 you need a 4x4,small turbo(escos)or a 500 t flow enough for 400 hp,grp A fuel pumps cost around £130 and like said above good idea to rewire the pump wiring!grp A headgasket is good for 400 hp although a small turbo one is even better