Guess I'll throw my 2cts in. lol. I prefer 1/8 for the big $$ races, and here's my take. A 69 Dart is like an aero brick. That last 660' pull against a digger or alterd, is giving up an edge. Areo and high closure advantages, are much more equal, in the 1/8. I also think it puts a little more pressure on the driver and the vehicle planner and mechanic. It's all tight, and it all has to be dialed and functioning within .005 to .01 around here.