The rubber isolator design superseeded the previous ball set-up design and is less forgiving, imho, if things are out of alignment. I think the rubber isolator was to reduce nvh in these cars. Without the rubber isolator the clutch rod will flop around in the hole in the fork. I had too many problems regarding the free-play with just the big washer against the fork and no isolator. I prefer the ball design because it fits into the cupped part of the fork and will still work if the clutch rod is not aligned perfectly. I do know that the ball set-up cured alot of the problems I was having in my Demon. I just wish you could buy the ball for $5 instead of having to get the clutch rod, nut and a new clip as an assembly.