Stacked pulleys will require bigger injectors for sure 550's are the most common but just about any tuner can tune for 650s or 750s on this platform. Upgrading to at least the SL55 fuel pump will give you piece of mind to not run out of fuel at higher demand. Do not waste the money on a looped fuel rail. The supercooler will not be enough to keep temps cool with stacked pulleys for extended or back to back runs. I would suggest at least a secondary fluid tank for the dedicated cooling loop for the intercooler and supercooler...or you can go KillerChiller and skip the supercooler and tank.