Tom, you should have no problems. Tracks and driving style obviously make a difference but here is my current setup and what I get. 2608.2g, RX8 with Pro4-4600 and either Reedy 4000 shorties or HVR 4000 shorties. The track is on the smaller side at roughly 80x110ft and is pretty loose. For the Pro4 class average fast laps are just under 24 seconds. Our qualifiers are 6min and the mains are 8min. I usually run four or so laps before the races starts and a one or two after the end of the race. With the extra laps and 8 minutes of racing my batteries typically take less that 3200 mA when I charge them. I have gone to 11 minutes and change on 4000 shorties before lipo shutoff when out practicing on my own.

Hope this helps.

Jason