the longer chassie with the 3.3 tames the wheelies down a bit. but as far as handling they are about the same.your handling will depend on your setup(shocks, tires oils and so on) i peiced mine together with things off ebay and other rc sites for less than what it would cost for a nice used one. when doing a 2.5 to a 3.3 you can use everthing but the front and back center drive shafts. well you'll need new body to fit the chassie. i loved my 2.5 and my 3.3 is a great running truck. 99% of all the parts can be swapped.
if you need more help let me know.