what to convert?

Ok guys, since my truggy has major diff issues I am looking for something new to convert. I will be using the brushless stuff that I already have. I have a MGT that would be cool, but I could trade that for a revo. The revo looks alot more challenging. What do you think? The MGT seems a little big for a 9xl, but if I went from 16 cells to 18 cells would that be ok? Opinions, suggestions please....