6s on a stock revo will mean shredded gears and other drivetrain components.
4S 5000mah Lipo 35C lipo
RCM Revo conversion
Tekno battery tray
Single servo mod - Hitec 7955TG
Castle MMM
Castle Motor - 1515 or 1518 if you can find one cheap
Lock the stock trans
Consider buying a 3.3 chassis and new centre driveline.