I really don't get the difference between those 2 classes but I think I could make my car meet either one.
I have wanted to put some spring boxes on my car for either B/E body or Chevy leaf springs with the longer front segment but that may be tricking the rule book a little also
I dont think the boxes would cause any issue... its still a stock item(just not on your car)... hell you could bend up your own boxes
