Normal
for 400,go for a better piston like u mention earlier accept 4age piston.i don'tthink that piston can take 400hp.remove ur xtra inj n change to 4X600ccinj for an even fuel delivery in each of the cylinder.lastly,go for gt30 turbo.for better turbo explanation,try jinkl or sum_dum_funk.they can guide uon which turbo to choose for ur application.
for 400,go for a better piston like u mention earlier accept 4age piston.i don't
think that piston can take 400hp.remove ur xtra inj n change to 4X600cc
inj for an even fuel delivery in each of the cylinder.lastly,go for gt30 turbo.
for better turbo explanation,try jinkl or sum_dum_funk.they can guide u
on which turbo to choose for ur application.