I have the MX6 and that is at the high end of weight I want hanging off the back. I leave the loader on, but there are times the front tires lack good bite. So far I haven't had a problem, but I don't like that light feel in front. I don't know how much more the MX7 weighs, but I would expect that the weight increase plus more length (hence more leverage) would put it into pucker mode too much for me. Horsepower is there even with my 4320, that would not be your concern. My rears are loaded, but that probably would'nt affect anything.