yes.. im sure you have driven over a speed bump before a little bit too fast.. you know how that feels now imagine that feeling on every single bump/crack in the road. you are shortening the spring 3 inches so there will be a ton of tension on them already they will not compress like they are supposed to and you will have a very bouncy ride. I cant even believe they make those kits to be honest with you it has to be the most unsafe way to lower a car i have ever heard of.