curbside

So, I have an 06 gt with a Saleen blower and forged internals running meth, no intercooler. Last dyno 496 rwhp 480 ft lbs torque. ''Tis is at 8-9 lbs of boost. My car was running rich after lots of tuning, I had someone adjust it, less meth and more lean. Car runs great now, was spitting and sputtering black before. It's running great now, just wondering how much hp gain above what I'm at if I go to 15lbs boost and add more meth/ richer system. I've already snapped my input shaft once; Before last/better tune. I'm sure I'll break it again, but what do you guys think of adding boost to max and adjusting tune?