There are probably more powerful Stingrays in existence, but the Z06 is in its relative infancy. So this engine upgrade package from Late Model Racecrafts that sees output of the 6.2-liter supercharged V8 upped to around 750 hp and almost 800 lb-ft of torque, makes this track-focused Vette the most powerful on the planet. It also makes it one of the best-sounding. The stock Z06 is rated at 650 hp and 650 lb-ft of torque, so that's a significant bump.
The Stage II package includes a 1.7-liter GM-sourced supercharger, but there's no other information about what went into the upgrade. If the tuner's other packages are anything to go by, this LMR program will be designed for both performance and reliability so you can thrash the hell out of it on a daily basis.