There are two problems with using anything other than stickpacks on the F201. The forst is with the kit chassis. There are plastic spacer thingies that hold the stick pack in place. 30 minutes of Dremel work will take care of that. The real problem is because of the "battery cups." They are rounded and provide rigidity on the right side, so you can't really Dremel them to make side-by-sides fit. These cups are also where the body posts mount to, so if you chop them up, you have no place to mount the body. I have the Cross chassis (sorry DS, I didn't get time to take pix.) It would fit side-by-sides easily if it weren't for the battery cups. I plan on making a plate that the body posts can mount to so I can get rid of the battery cups. This should also make a solid place to glass tape the battery to. I'll let you know if this is going to work.