I made the opposite mistake and thought an E-Slayer would be awesome so converted my E-Revo to an E-Slayer. HORRIBLE idea.
Things I used were all new arms, shafts, pushrods, different springs, rockers, and wheels/tires. Sounds like you got it covered.
As for what wheels to use, I would say use whatever you like best or can find cheapest. The difference between the 2.5 and 3.3 chassis is fairly small and the shorter length with bigger wheels may give you more of a "Jeep" effect and climb better.
Good luck with the conversion. It's not hard. Lets see some pics!!!