I got my 2.5 jato acouple of weeks ago just before I found out`that traxxis was comming out with the 3.3 jato so after talking to serval hobby shop guys upgraded mine to the 3.3 engine and yes it fits right in the same area as the 2.5 with litte problems had to do some minor trimming to the body around the back to allow the cooling head to fit better (about an 1/8 inch) but other than that it fit just like the 2.5.
put a 24 tooth clucth bell on her and a tune pipe jp1 resnanator and broke in the new engine breakin was fast and easy (dosn't take long to suck down a 75cc tank) about the 3rd. tank so started to come alive and after the 5th tank she really started to roast the tires. looking to put the sway bars and wheeley bar on her next to inprove the handling and prevent the wheely's so much when I can find them all the hobbytown that I have been to havn't recieved them yet from there suppliers or traxxis hasn't sent any out yet (i'm a cross country truck driver so can shop differant hobby town all over the country) but on dry and clean pavement she really flys weight transfer is slow so cornering at high speed she will flip and summersalt really easy and the brakes suck but who wants to lock up the brakes at almost 70miles an hour not me but it is fun to find an open parking lot and let her really take off and run faster than the wind