You'll need a GT3071 imo if you after 400 or just over, as said above, T34.63 will make that number (maybe) but won't last long and that's a fact.

I'd go for 83lb Injectors, although 55d will flow plenty enough for 400bhp, but if you want more future power then the 83s woyld be fitted

Level 6 ecu will be fine, but again, i opted for Level 8 on mine

Group A HG would be fine also but if you're having an engine out job the WRC style maybe??

Cam choice, go ABO7 as i've heard great things about it mate..

Als imo Live map will be better if costs allow