I put a Sportwerks .26 in mine...(used in the Mayhems) it's the same motor as a Dynamite Mach .26....very good motor....tons of power and easier to tune than the Infinity....one other cool thing about it is that it came with three different carb inserts also.

$130 from Horizon hobby.... http://www.horizonhobby.com/Products...ProdID=SWK8085

I actually found it on Horizon hobby but my LHS matched the price for me....great motor for the money.