The engine is quit good. I put 23psi with garrett gt28rs on my engine. STOCK INTERNALS. Only another ecu, (stock ecu with dynotuned fuel table).bigger injector, fuel pressur regulatorand 6 paddel sinterclutch. Also bigger intercooler and decat exhaust system.No problems
But more important than the boost level is the ignition timing. With the original distributer you can not put the ignition timing with that boost level in an incredibal condition. If you want to take a ecu like megasquirt you have to put in better rods ands pistons to use harder ignition timing.
In the future i will go with megasquirt and electronic ignition system. I will begin with around 16psi of boost with tuning.