I put air lift 1000 bag's in my spring's. You can adjust height individually with a line to each bag, or with a t fitting to raise both up at one time . I have mine separate so i can level out if needed, all fitting's come with kit. Yes these will raise and yes it will ride firmer in rear if you inflate higher pressure's.I only raise the rear about a inch and a half.Stock height just look's to low to me even though i have new correct spring's.If you carry heavier load's at time's you can raise to desired level.That's what is nice about these you can adjust anytime.