The 3.3 is a fine "RTR" engine if you know what to do with it. Understand that it will have air leaks, is very tight and must be around 200 degrees as much as possible during break-in, and will need new bearings sometime after that. I wouldn't let the 3.3 sway my decision on getting a revo, they can fetch as much as 140-150 bucks on ebay (nib), which is close to the price of a good replacement.