The problem is at what point does it retard so much timing thats it's no longer even making power and losing it.

They already knock from the factory, adding more boost will make it worse. Adding race fuel will lower the knock for sure but you are still on a fine line with stock everything else.

I mean you could go ahead and put a 3.0 or 3.2 on there and let it rip, but it might only last 1 pass and chip a piston.