You will need to get a new ESC/motor combo for 6S. The Rivals factory powertrain is its weakest link. It is an animal of a truck though. I've had a Rival for 8 months now and I use it hard and love it. Everybody and damn brother seems to be a fanboy of the Savage Flux with XL chassis and after years and years of reading about how great they are my curiosity got the best of me and I got one. Now the I have the both of them I can tell you the Rival is a better truck in more ways than not. It handles more truggy like than a Savage so its flickable and more predictable in the air. I can launch my Rival off of jumps that send it 15 feet high and 30 feet long easily. Its kind of like a buggy/truggy in the fact that it mid air corrects nicely and tends to level out almost naturally. I could see selling the Flux XL in favor of another Rival but most likely it will just a Tekno ET48 this time around. BTW the rival is 1/2 inch longer and just as wide as an XL so don't the XL part of it fool you into thinking its a bigger truck, its just a bigger piece of crap.