Coil overs on all for corners in the hands of the right guys will allow them to dial in the cars suspension for launching and traction that would be costly and time consuming for a person using the factory style set up to match. Limiting things like this is what keeps the field closer in ET. I don't think coil overs need to be in the class. Cars can clearly get in the mid nines without them. When setting rules, as mean as it may sound, you want to do as much as possible to keep TSM and monster TAI cars from fitting in to the class. Keeping out cars closer to what the fans have and watching what they can do is what makes THS and TAI so fun to watch. I love the TSM and monster TAI cars and racers but the 4th graders are never excited to play dodge ball with the 6th graders.