The Velo Rossa™ is designed to run without bumpers, just like the original GTO. The Daytona can be run "competition style" without bumpers, or with the bumperettes like on the street Daytonas.
The other kits can be run with or without bumpers. Whether it is legal to run a street car without bumpers in your locale is up to you to determine. Generally, though, it's only an issue at time of registration if/when you have to have the vehicle inspected. I've never seen a ticket issued for lack of bumpers...not to say that you absolutely WON'T get one, but I think it's a long shot. Most reasonable folks I know see bumpers as being for the protection of YOUR vehicle. If you don't care, why should they?
I do offer, but have yet to post to the website, fiberglass bumpers in both 240 style and late 280 (1977-1978). I have plans to also make molds for the early 280 (75-76) which I think look a little less clunky than the late bumpers...though a lot of folks like them. If you are interested in this option, please contact me via the information below and I will work up a price for you.