Old tale... but how do you get 530 H.P. from a 3.7 GTR and only 280 H.P. from a TSX 3.5 V6? What mods would be required to get the TSX up to say 400 HP? Twin turbos? DOHC? Different internal materials to rev higher?

 

Twin turbo helps, ECU tuning, the .2 difference is proly compounded by the fact that the manufacturer designed the GT-R to be performance car whereas the TSX makes a nice cruiser....the mindset of creating both cars is so different which makes the disparity really "WTF"

As for mods a custom Turbo or S/C is the easy way but doing some porting, boring, changing how the air inhales and exhales in addition to a reflash could possibly get you there too

(All based on pieced together info and assumption)