KingzJ....I have been racing UMH's all summer in stock and mod TC and they have only lost 20 sec of runtime and the voltage has increased. It all depends on how you take care of the cells the UMH cell does not like to be charged hard and put on a tray to discharge. If you charge them at 5 to 5.5 at 02 cut off on a T30 and discharge to 5.40v they are fine. I have yet to run the 3300's but I just got a pack and all I can say is mega runtime and ok voltage and higher but not as high as HV's IR. If the IR of the 3300's will always be this high I cant see them being better then UMH's. The UMH's are about 15 to 17 on the IR and the 3300's that I have seen are 20 to 22 so this seems to be a little high and HV's are higher yet like 22 to 24. I belive that you want the lowest IR and most voltage for stock you dont need anymore runtime, now for mod thats another story.