I have recently installed a set of H&R Springs on my 2015 SHO and am pleased to say, the results are fantastic. Highly recommend. Impact I measured from the middle of the center cap to the fender rim. Before Front: 15 1/4" Rear: 15 5/8" After Front: 14" Rear: 14 1/8" Front drop: 1 1/4" Rear drop: 1 1/2" Pros Dramatically reduced front end lift on take off which results in a stronger feeling acceleration. I can't say for certain that this improved my 60' time, but damn it sure launches hard now. Significantly reduced front end nose dive under hard breaking. Strong and aggressive stance. No more "ass up" look and car feels very stable. Feels more like a true sports sedan now and really compliments the factory SHO performance improvements. No binding or rubbing on my stock rims/tires after 500 miles. Superb feel on the highway, feels much more responsive and stable at 70+ mph. Cons Ride can get a bit stiff over poor roads like we have here in MI. Can get a bit jarring so I compensate and just slow down. Need to go slow when turning into driveways and the like. This isn't really a con, but you need to be careful. You could rub if you get to aggressive.