I am using the 3.3 until it's tired. Then putting in the .26 until it's tired and then probably going to stick with the .28 after that. I have 3 brand new engines. I just like having the parts around and options. Me and my wife just finished building a rd logics aluminum case tranny with rrp steel gears. I have to put in my set of traxxas steel cvd's and I already put my wheelie bar with the upgraded wheels with bearings on it. It's to cold to run the 3.3 revo to beak it in. So me and my wife use her e revo and the kids evader ext to play in the cold.