I just got this ultra mbx and replaced alot of parts on it, and first time out (about 5 min) the throttle servo must of been broke and it screamed full thottle and hit my yards fence about 30 feet away. It felt like it ran perfect, when I got to it I shut it down by caping off exaust, I fixed the servo that nite, and when out to try it again the motor turned over hard in one spot (TDC). My question is, What motors can I put in that are readly availible, I have so much into this now, I hate to think I'll have to spend hundreds more. I see alot of t-maxx motors on here and ebay, would one of them mount in place and if it does mount, does anything else match.Thanks...Dave