mf2 or rusty?

[t-maxxracer32]

i can get my hand on a mf2 with a bunch of tires for 175 with no electronics or anything. but i have all that stuff from my rusty to put on. would this be a big improvement from my rusty? it has some decent upgrades
(rpm arms, carriers, steel yokes, alum idler and i got a lot of tires and rims for it...) but the guys at the track say the mf2 would be a MASS improvement over the rusty. i either buy this mf2 or new batts for my rusty... so which one should i do!!

lmk