Good choice on the motor. You won't need a lot of AMPs for the Mega. Here are some options:
http://www.rc-monster.com/proddetail...TMM80123sHCS01 (I have this one on my TC3 Truggy with a HV4.5 motor. No cogging at all).
http://www.rc-monster.com/proddetail...oadster&cat=21