I ran the 3600's for Off road last year and liked them......they seemed to perform as well as the 3800's I had from IB.....My son still uses them in his T-4 in the kids classes and the run time is still there....I can't say anything on the 4500's.....the classes I run now use ROAR rules and only allow approved cells.......BUT....If rules aren't a factor I'd try a pack or two based on the experience with their 36's.