How much difference will it make?

just my humble opinion... slicks would just mask the problem(s). Anyone take a sneak peek at some of the times ran on 26x8.5 or 9" drag radials ??? yeah....
.....and I'll bet they aren't Nittos. If slicks cure the problem, than he can play with solutions for making his drag radials work.
Of course, if slicks solve the problem, he may not bother.