It looks like it's time for me to take my car back to have the map checked and adjusted so was thinking of upgrading the turbo at the same time to save on paying to be mapped twice.
Current spec

200 block with valve pockets machined in to pistons
Mild polish and ported head with ba16 inlet std exhaust vernier pulleys
T34/63 turbo holds 28psi. Air injector boost control
Pectel T2 management and loom.

The block wasn't long studded when built as wasn't going to run 400 + bhp but was fitted with ARP Stud and nut kit. A few people have said I can't run anymore power as will crack the block because of the ARP stud kit if I fitted a bigger turbo due to it trying to lift the head.

My question is can I change the turbo for say T38 or maybe a GT30 without any problems or am I stuck at the current power unless I strip the block and have it long studded.