i've just finished my 4th gallon in a 2.5. its still running pretty good. starts on the first or second pull. but get this. i sold a rustler with 4 gallons through it to a friend and he got 1 and a half more gallons and it needed a rebuild. i'd say that's pretty good. i've never had to rebuild an engine. (probably because i dont drive it every day.) but i just had a big wreck (trying to go off a ramp at full. lol) and broke the rear hub carrier and another part up front. i've only had to replace 3 or 4 parts while i've had it. (about 1 1/2 - 2 years)