I got one of those once.....I couldn't figure out where to hook the fuel line to it?
I have always been an OS fan. And like deputybill705 mentioned, that is a direct drop in for the Traxxas 3.3. Great engine, power thru the roof. But depending on your budget can be expensive.
An engine I'm just recently getting educated on myself is the LRP. I've known about them, but always just went OS in the past and never really gave them a look. But seeing many of them out there getting exceptional reviews I think these are worth a serious look. And lots cheaper than the OS engine.
Weight, drive system, tire size, terrain type, suspension....... Yea.... it does make a difference. You might want a smaller higher reving motor in something such as the 4tec, and something with more bottom end in a revo to get it off of the line and going.