The back end of my 2005 RMk 900 is sagging, alot. Thought it might be the shock so I changed from the shock to a rebuilt Fox Clicker. Still sags. The minute I remove the sled lift it sags about 50% and if I sit on it goes almost all the way down. Do I need a different shock or do I need a new torsion spring? If I need a new spring should I go with the heavier one 7041942/43-329?