Can only speak from my personal experience.
2016 Camaro SS A8, mods are Maggie, Rotofab, Borla Cat Back.
- Stock Fuel System, 91 octane - 550 RWHP - 98mm pulley
- Stock Fuel System, 50% mix 91/MS109 - 612 RWHP - 90mm pulley
- Stock LT1 Injectors, Lingenfelter Big Bore HPDI pump, 91 octane + 70%water/30%meth injection - 620 RWHP - 85mm pulley
- Stock LT1 Injectors, Lingenfelter Big Bore HPDI pump, MS109 + 50%water/50%meth injection - 688 RWHP - 80mm pulley
- LT4 Injectors, Lingenfelter Big Bore HPDI pump, ZL1 in-tank pump, MS109 + 70%water/30%meth injection - 694 RWHP - 75mm pulley - need belt
And that's where I left it last Saturday, didn't have the right size belt to go with a smaller pulley, so picked one up in Sunday and will be looking for more power later this week.
It also might be time to consider adding some more exhaust components. I'm not looking to lose the stock cats, but I may add the shorty headers I bought a couple months back to see if they have any benefit.