I have zero experience with changing the springs, but I did put the super atv spacers in my Xmr and that raised the ride height about 2-3 inches. The reason for doing so was because when I was on a trail ride I felt like I was bottoming out a lot, but thought I couldn't be because I wasn't even pushing it that hard. When I got home from that weekend I noticed the stock shocks only used about 2 inches of the total shock travel. After putting the spacers in, the entire travel of the shock is being used and it increased the ride height. As for the ride quality, I don't think it really affected it too much... I also took out both sway bars at that same time the spacers went in so I'm not sure if that was the reason for not noticing a huge difference in ride quality.
I know this really wasn't an answer to any of your questions, but just wanted to give my input if your questions were aimed toward getting more height out of your suspension.