I'm running an e revo 2.0 tranny in my e maxx vxl with the cush drive and traxxas steel center cvds. The only mods I had to do were machining a small amount of plastic from the chassis so the transmission would fit through the chassis opening and I had to mount velcro battery straps because the motor mount doesn't allow the 3s batteries to lay flat in the factory battery tray. I also had to mount the esc vertically on the rear shock tower but im running an SUV body so its wasn't an issue. I used Unlimited Engineering 7.5/8 gear spider diffs and they are bullet proof. It was a fairly simple build and it makes the e Maxx a beast.