Installed new Progressor adjustable front spring spacer on my 06 500efi. Wow! what a difference. I put it on #2 setting and it took the sag away and still rides awsome. I also adjusted the rear two clicks, Whole new quad. I love it. $79.00. Haven't tried #3 yet. #1 is suposed to be stock, but it too took the sag away but a little soft for me. www.t-m-2.com Cheaper than new springs and adjustable. Easy install. Took about an hour. Came with great directions. I think Polaris also sells them.