Randy – Great question. The main reason was to limit the number of differences between the cars so people would not have to spend more money or more time going to the track to try out different options to find the best set up. It’s better in these proxy races if the parts can be kept as similar as possible between all the runners. I thought everyone would have a short can they could use as those are the same motors we use for just about every other series we run.
The last Group 5 race had rules that were much more open and allowed racers many options to find the fastest car – just like the real Group 5 rules.
Marty