Can you run fenderwall headers on the street

You can make a heat shield for the MC or buy one...……..
Master Cylinder Heat Shield
With the cooler temps of fall/winter a little header heat might be a good thing for some folks.
I believe 25" tall tires are ok on the straights. Hit a small bump on a turn into a driveway and you'll likely rub the tubes. It's been more on the passenger side in my experience. How much rub also depends on your suspension height. I never hit anything that affected the header while it was on the road.
I've seen more than one person bend new fender wells down while backing off of a trailer.