Handling is improved over the stock springs because the RM's are firmer so you have less body roll in turns. Secondly because you are lowering your car 1.25 a little more negative camber is added in the front which makes your turn in response quicker. The car doesn't push like it did when it was stock. The most obvious improvement is with quick lane changes and on ramps. The balance of the car feels better. Ride quality doesn't suffer much because the RM's are progressive. I had prokits on my car before and these are a lot more comfortable for daily driving. Excess wear on your shocks is negligable and bottoming out is nearly impossible. I'm on 1.75" RM's and I accidently launched my car over some train tracks that I was unfamiliar with. For the split second I was in the air I thought that the landing was going to be really ugly but the landing was soft and I didn't bottom out. Bottoming out with prokits was a weeky ocurrance even under less extreem conditions. RM did the R&D before they put these into production. I don't know about install pricing because I do my own suspension work. If the springs are installed correctly they don't make any noise. Seriously I can't really think of anything bad to say about them.