Yea, I went to radials on my car several years back and picked up like 1/2 a tenth.
That said, if I was bracket racing on leafs I would be all about a bias tire. WAY more forgiving. Way easier to get to work.
I put a Mickey radial on my old Duster I mentioned upthread and it went up in smoke no matter foot or brake. Put the bias tires back on after 1 night of trying to make the radial work on a very good track.