The rear springs on my 02 mxzx 600 seem too soft. When I sit down on it it sags 4 inches and doesn't pop back up when i get off it. I was wondering if anybody else has had this problem. Also wondering if rear springs off a 02 440 zx would fit on it. my springs are turned all the way up on the blocks too.

If you weigh more than 200/220 pounds or you are very aggressive and either way you bottom out hard, then you may want to concider getting the HD springs from your dealer. Bottoming out now and then is okay. You just dont want to be bottoming hard frequently while on every ride.

You should have some sag, even with the HD springs the weight of the sled may cause the rear to sag a little.

Good luck
Todd