[MetalMan]

Ideally you want to pick a motor of the appropriate size for your vehicle (for power handling). Unfortunately the knowledge base of outrunners in cars/trucks is very limited, so finding the appropriate motor size could be hit-or-miss. But after you do find a good motor size, check out what kv options are available. For the CRT.5 I think 3s Lipo is a good all-around choice, so I'd pick a motor with a kv of about 1000 for 4" tall tires and about 40mph top speed.