How much boost is safe

[DSM_421]

to run on my 1993 Eagle Talon TSI AWD five speed.

All the engine mods so far are as listed...

New 91 (big rod shortblock)
New Head by Headworks
ACT 2600 Clutch
Ported 95+ Exhaust Manifold
Ported o2 housing
Big 16g Turbo ported and modified by tre engineering
3" Stainless Steel Downpipe, Cat, and Exhaust
95+ intake and MAS
Buschur Racing Front Mount Intercooler Kit
Magnecore Sparkplug Wires
Walbro Fuel Pump
550cc Fuel Injectors

It hasn't been boosted above 15 psi but I'd like to turn it up a little.