The easiest and best thing to do is a full conversion to Heng Long electronics. you can buy everything you need except the gear boxes in a kit form. It's the S&S conversion kit. You can get everything from RCCommand, and Bill will be happy to help you out. I have the Hobby Engine LEO2A5. I'm actually in the process of fittng Tamiya tracks and sprockets from their LEO onto mine. i'm using my old Tam Panther gearboxes. I am having custom shaft adapters turned to do this. Then I'll most likely be converting to a full El-Mod kit. From Phil at RCTankWars.com . I think thats the correct addy.