That would depend on what kind of system you want to put in it but I'd start with switching out those driveshafts and try to find some metal gears for the trans. If you plan on using the MMM 2200/2650kv or the like you should also look into those diffs. A system like the one pictured in there should be plenty to make the truck fun and reliable but would be nothing like the newer chassis rtr brushless trucks in terms of power.