Fasty, welcome aboard! As long as it's 9.6v, you should be fine. The more mAh's you have the longer your run time and you should always try to find the most mAh's when buying a new battery. Are your current 1000 packs nihm or nicd? How much run time are you getting out of them? You could also try to hook your batteries in parallel (
http://www.zbattery.com/Connecting-B...es-or-Parallel) by buying/building a Y cable and mount one battery in the stock location and one out front for more weight over the front axle. That way, you can disconnect them to charge them because if your charger is like mine, I can only charge up to 8 cells. Keep us up to date and check out some of our other post in here, you may get inspired as I did...