T4 is a reliable 2bar turbo mate many peak them at 34psi + though LOL. Very laggy though really. What you want for the road is:

T34 .48
803 injectors
Grp a/escos head gasket
3bar map
pf09 tps
RS500 type intercooler
NMS or MSD map

350 max bhp but so fucking drivable on the road!!! Best cossie road conversion going the proper strage 3