You can just get the Traxxas Velineon 3350 system which is waterproof and runs 2S and 3S lipos. You can find some on Ebay new for around $140 for the ESC and motor. They are great for the 2wd Pede but still almost too much power sometimes unless you get better tires. You can even run the Velineon system with a 7 or 8 cell NIMH 5000 mah battery and it will be more than enough power. I have run this setup in my 2wd Pede and it would spin the tires like crazy and push the front end. There are cheaper ESC and motor combos out there, but they arent waterproof.
Anyone want to buy some of these money sucking, space taking, addicting rc things? They are taking over my wallet, my house, and the trunk of my car!!!!