IMO a LOT of the reason to go 1/8 mile S/Pro racing is the speeds cars are going nowadays. Which I am sure insurance rates have a part in. For instance our dragster will run over 190mph and there are plenty faster or as fast. IMO gone are the days when 170 was a big deal 1/4 mile racing. Heck our car goes 153 in the 1/8. I think this is a driving force for going to 1/8 mile at least in top bulb/s/pro racing.