By the time I sold my Slash the only thing made by traxxas that was left was the diffs and maybe body posts. It was tricked out to the maxx and I still sucked really bad driving. WIth this Tekno I dropped my average lap times from 45-47s to 34-33s consistently! I wouldn't even move the battery tray back I'd focus on your electronics, camber, ride height etc, let the battery mod be the last change u have to make only because your really concerned about weight distribution..