I have to agree with Rob Kz1/2 is not only a one of the most competitive classes but its one of the cleanest, if you watch live streams (or tape delayed) of Kz class drivers is nothing but good clean driving. Maybe that’s something to do with the fact that KZ engines have the bottom to mid range that if you drive off line you can still pull out of the corners after making a pass with out immediately getting over undered. The issue in classes like KF and KF3 is the engines are notoriously boggy through the mid range and that makes passing, well for lack of a better word annoying. I’m not saying punting is OK or right but punting a guy wide instead of genuinely passing him gives you more time to really get up to speed.
Also Australia runs both full and frame width rear bumpers in every class they still see punting still see rough over aggressive driving and they see some horrific crashes. I’ve watched videos of Australian driving and i have friends who drive in Australia it doesn’t make a huge difference with bumping and such because if there’s a will there’s way. Even if you can’t hit the corner of a kart to punt someone you can still load someone up in the center. Sure its going to change how people punt and make it harder but people are still going to find themselves out of a race from a solid bumper shove.