Thabks for that. I’ve added a 3.75 pulley to the list. I was looking at Whipple website and they claim you can make over 1k on 93 at 15lbs of boost. I would love to know what setup they were running.There's zero room for 93 octane + a 3.25 pulley, you're talking 20lbs or so of boost far surpassing the detonation limits of 93 octane. A 3.7 upper is doable on pump gas and a slight, slight possibly of a 3.6 upper pulley. I'd say the vast majority of tuners are going to shy away from anything +17lbs of boost on 93 pump gas. Engine WILL go BOOM. Pump gas 3.8 upper pulley = yes, 3.7 upper pulley = yes smaller and your crossing into dangerous waters.
For reference: 3.8 upper I'm at 16lbs of boost @ 8000k redline / no cats = less restriction / backpressure = less overall boost. Cats might pump up the boost by 1lb or so with the restriction in the exhaust.