Just installed sprint springs this past weekend, and so far so good. I was going to go with ground control's + retaining spring, but decided on the sprints b/c of price and the drop. I drive 3,000-4,000 miles/month and didn't want the ride to suffer too much. Sprint does not publish the spring rates, but did tell me that they are 27% stiffer than stock, and they are also progressive rate like eibach, teins, etc. To be quite honest I think the ride is better than stock, and that's with 18's as well. As far as scraping goes, my driveway is pretty steep, and I have yet to scrape my wind splitter or exhaust upon entry/exit. For what I was looking for I give them two thumbs up!