No race gas? Fine… go E85!!! I’m running E85 and just over 600rwhp NA with a stock 85mm MAF and stock Ti catback on my car. Speed Density with an better exhaust and it might have 620+ in it. With boost E85 will help you even more. And with all the motor and plumbing in such a small space the cooling effect will be huge for you as well. Seriously, I thought somebody said there were pumps in your area, you should think about it. And you said the fuel system can handle all you can throw at it, so hopefully you won’t have to make changes there (figure you need roughly 30% more fuel). If you’re over 60% duty-cycle on injectors now you’ll want to bump those up. FWIW I’m running 80# injectors to support my 600rwhp, but I’m actually really low duty cycle (which I like) eve on the E85.