knuckles/uprights are the same on the 1 & 2, and are also the same as the new Nitro 3 Evo which I also have. I know the MT2 also runs the same uprights, but the knuckles MAY be different. I'd have to go look, but I think they are the same.
I think the a arms are beefier on the 2 vs the 1. I'm sure the 3 is a totally different design as I think it is also shaft drive. I have a race buddy with one that I can check out when the season starts at the end of this month.