Have you already put in the order for the monster horsepower motor? reason I ask is that these motors can sometimes have issues since they are high on the RPM side of things.
You may want to go to www.rccars.com
and check out the motor suggestions they post.
For truck I think a p2k2 or MVP would work well. I have the MVP and the P2k Pro and they really work good for truck.
As for threaded bodies, honestly I never had the need. I just got some RPM clips and they worked quite well. They are easier to take off since they have a bigger lip area and they also seem to stay on better from hits.