Andy, i'm in the fence, as well. i'm not saying tat upgrades are essential; but after a while... you're gonna want certain things. like, let's say, CVD's instead of plain dogbones. you're looking at $25 per set. if you want to run LiPo's (correctly, not hacked), the HPI/HB upgrade is $50 for a piece of carbon and a piece of aluminum.
Charlie... you're the man. =)