Just wanted anyone interested to know that I installed the AD Boivin rear coupler kit on my 98 ZR600 EFI LE and it is a HUGE improvement!!! I put 150 miles on last weekend with the new kit installed, and it made the studder bumps disappear, and the big bumps a lot of fun to launch off of! It stiffens up the ride quite a bit, but the benefits in control and handling are unbelievable!! Highly recommended to anyone looking for more control out of their ZR. I ended up getting a great deal on it and was able to pick it up for under $80 bones. A lot better than the $160 I was quoted for the Arctic Cat kit!!