My uncles both have 800etec one in a xp chassis 163 and one in a XM 154. The XM has about 500 miles on it and gets eaten alive by the xp. He said that the rpms are good. When they do a climb together the xp will climb way higher. He hasn't done the new reflash yet but not sure if that makes a difference. Please help my uncle out or he will keep riding my arctic cat...lol