This may seem like a dumb question, but aren't the LH and RH rear coil springs supposed to be the same height before installation? My local NPD parts store pulled 3 different "sets" out of the box and none of them matched and when I asked that question I got a blank look. Also, what should the "free height" be for the heavy duty stock spring and is there a brand that is better than the rest? I'm going to be replacing the original sagging springs and aftermarket air shocks and am hoping to get the rear end to sit maybe just slightly higher than stock (1/2-1")and want good ride quality(Michigan roads stink). Thanks, Chuck S.