Guys,<br><br>We really appreciate the suggestions. We're trying many of them.<br><br>BTW, it's helpful to remember that each local derby establishes its own rules. Thus enormous variation exists as to what permissibly can be used. Our individual derby's set of rules is pretty broad. We find it worthwhile to explore the options to maximize each car's speed. That also encourages imaginative approaches by the boys.<br><br>Thanks,<br><br>John