Here is some other good info for you guys:
Ending voltage - 5-minute race - 1625mah used on a 13.5 BL Novak Sintered Motor
3200 LiPo - Ending Voltage = 7.570 Volts = 24981 rpms
3600 LiPo - Ending Voltage = 7.660 Volts = 25279 rpms
4800 LiPo - Ending Voltage = 7.844 Volts = 25886 rpms
5000 LiPo - Ending Voltage = 7.866 Volts = 25958 rpms
7000 LiPo - Ending Voltage = 8.018 Volts = 26460 rpms
I think's it obvious why capacity is most important specification for a battery, as higher average voltage over a 5-minute race means more power, and more speed/rpm capability. I don't know who makes a 7000mah battery that fits a TC, but if there was one, it would be nice. The jump from a 3200 LiPo to a 5000 LiPo is obviously better.