I dont think the S 4 is making 450 whp because there is no FMIC, yes u can put 450 whp with KO4 but boosted at 25 PSI which is the max for the ko4 and by passing the N75 but to do all that u need a FMIC to keep it cold lol
oh yeah u need a 3' TB no cats ..... and some more shit. .any way is ver hard to make that power on the k04 and keep it mind is not a TWIN tubro is a BI TURBO.