STI 8 i'm taking it is your car due to the sig. The STI 8 TMIC is very good i would say there is no need to replace it to see 400bhp. Plus the last i remember is the hybrid is still only made for classic shape.
Andy's 18G's seem to be the new in thing and should produce 380bhp maybe a little more.
This is what i would do
walbro pump
SX reg
18g turbo
full de-cat (open neck) downpipe
Ecutek remap
ported headers