It's all in the tuning, but the max I would go with a perfect tune is 12 psi. I have seen some D16z6 putting down impressive numbers on stock blocks and 15psi, but they don't last too long. 10 psi is good for a daily, or you can use a dual stage boost controller, keep it 6-7 daily and 10-11 as a high boost setting only one push of the button away.

I'm tuned at 14 psi low boost and 20 psi high boost on the WRX. All I have to do is hit the button if needed.

Also one thing to consider is that 10psi on a junkyard T3 and 10 psi on a brand new turbo, will give you different numbers. Also the trim size of a turbo will affect spool up time and air volume going into the engine.

But 10 psi on a completely stock block with good tune you should hit around 200whp