I did my xr2i years ago ,matched the inlet manifold with the head ports as they were smaller and gas flowed the head (sorry power zone stage 1 new head

) then gas flowed the inlet manifold. Reconditioned the engine ,big exhaust ,super chip ,kent cam kit, venom induction kit and split fire triple platimun spark plugs. It got 116 bhp on dyno with timing out by 3 degress. Better then 108 that it started at. A nice 8 bhp gain and £1000s spent.
