Wow why do you want more range? I just got my first Zip Zap yesterday (a Ford Torino set and loads of RS upgrades) and I'm completely delighted with it. It's just soooo superior to my BCG Pro in every aspect. But what amazed me the most was the range. I stood in one end of the hallway in my apartment and could drive it all the way to my parents' bedroom
Meanwhile my BCG can barely leave my room and keep moving. I've fallen in love with Zip Zaps
But anyway, range is never enough I guess
Good luck modding it!