performance i'm hopping will still be worth the extra though, talked to the guys at the hobby shop and they recommend the RB 728 because it's got more low end then the 928 (soposedly better for bashing but i like the TM523 over a picco max as a basher), and the 728 is $100 cheaper, i still think the nova or 928 though, and since the hobby shop stocks RB engine, but will only order in the nova i'm leaning to the 928 at the moment.

(then again the guy at the shop tried to convince me that there was only a 3 port version of the nova, no 8, and that apart from that the 928 and 528 are exactly the same engine )