Quoting clevr4:
This bigger turbo idea has really stemmed from a friend of mine with a neon srt4 spanked me off the roll. I'll inspect my current setup and leak test the intercooler. 3 inch straight pipe exhaust.
Yes, do a boost leak test. With that blow through MAF, you could be leaking and not know it. Get that checked to 25psi, or even 30psi.
To me it sounds like you really need to run it into a dyno shop and have them play with the tune. That turbo should be pushing over 400hp on pump gas. I think you need to get it running right and get your boost turned up to around 22-25psi. If the engine is in good shape it should hold it.
But, that's where broken axles, blown clutches, shattered trans happen. Big power comes at a cost, so be ready to fix broken parts when it happens, and it will.
Nice set-up you got, really just need to get it all sorted and cleaned up and you'll be in good shape.