Hpi, traxxas, o.s., sh, and lrp are some more popular ones. I know hpi idle lower and are easier to tune then trx. With the trx 2.5 and 3.3 you have to watch the plastic carb.
Ebay has parts, rollers, and chunks of used cars. I was looking yesterday. Congrats. I always wanted one the day it came out a couple moons ago. 🫠
https://www.ebay.com/sch/i.html?_nkw=nitro+4tec+gear+shaft&_trksid=p2334524.m4084.l1313&_odkw=nitro+4tec+transmission
Rear pulley should be the...