No. Not without data logging the car fist of all to check for knock and only then can boost be increased in accordance with those results and gradually, in increments of 0.5 psi.
The chances are that your injectors aren't actually flowing the stock 360cc of fuel anyway, unless they have been serviced at some stage recently.
I will be doing a write up on this very soon, as soon as time permits. We have an ASNU machine for these purposes.
We service the injectors on every engine build we do and have seen as much as a 25% deficiency on flow rate on old worn injectors, that's quite alarming.
To increase boost on a stock engine; Make sure the engine is fully serviced, this includes fuel filter, oil/filter, plugs and probably leads and ensure that the cam belt service is within date and has been one in it's entirety, not just the belt, as belts never fail of their own accord on these engines.
Data log the engine to see what is happening with IDC's, knock, lambda reading and timing.
If only one of those is out of spec you WILL blow up the engine, melted pistons etc.
There are other precautions that can be made, hot wiring the fuel pump is one good modification for this area.
There's plenty more to add but i'm currently at work and don't have the time to detail all the finite details.
One other bit of advice, don't use a bleed valve control for regulating boost, they are another form of time bomb on these cars.
If you want to control boost, use an EBC, such as A-pexi' AVCR, these are superb and work extremely well on most things, GTO's especially.