Solara thanks for the info on the battery thing. I have all 5000 packs and seems like with those you need to do a little modding to get them to fit. I read about the motor thing a little but not 100% clear on why some motors fit and some don't. I'm just not sure what I want to do at this time car wise. I will say that the design is very nice and potential I think could be huge. Sounds like TM would do a little more work on some of those little issues they could have even more people running the car.