If i had all the money i needed I would engine swap but then again the ms3 is fwd and therefore you cant add too much power. Forged internals . . . new pistons . . . new engine block . . .the whole 9 yards.
Spark plugs
CPE turboback
SRI
forge bpv
cpe fmic with sprayer
meth kit
H&R springs / coilovers
front / rear sway bars
brembo brakes / pads
carbon fiber everywhere . . .
nos kit just for kicks
cams / better clutch / flywheel
engine mounts / shifter upgrades
upgraded turbo
tune
exhaust / turbo manifold
turbo timer / defi guages / boost controller
fuel pump
crankshaft
oil catch can
and tons of stickers
That should put you around 360 whp. (if you dont engine swap)