Mountain- I've decided to go 850/860 (heavy front, medium rear) because I will have an ARB bar but no heavy rear bumper (just a Kaymar tire carrier attached to factory rear bumper), and this spring combo should negate the need for trim packers (spacers) to level the front end with the ARB on it. You are right the spring rates are the same for the medium and heavy so I would assume ride would not be much different if combined with the same shocks.