Bluetop on turbo

[leon205gti]

Hi there, on my slow turbo bluetop project, i was planning on stay all stock and run it low bost 5/6 psi max. But the other day i,ve realised i have a tiny coolant leak between head and block, closest area to firewall and its probably to take out head to repair it.

On the way i was thinking on place a thicker head gasket to reduce compression so i can increase psi on turbo. How much bar ps psi can i run with stock internals and dropped compression?
Where can i find a thicker head gasket to drop compression to 8 or so to 1?

Cheers