Not at all. The original equipment coil springs have already settled and so the end result will be superior to aftermarket springs that haven't settled yet. The ride will also be superior to aftermarket lowering springs.
Read the book, "Performance Handling", by Herb Adams VSE, a respected suspension engineer. Herb Adams designed the high performance handling package for the Pontiac Trans Am. He doesn't use or recommend aftermarket lowering springs. Quite the opposite. Instead he cuts the original equipment coil springs for superior results, with both street cars and his 24 Hours of Daytona race cars. All his development cars, Camaro/Firebird, GM full size cars, Datsun Z cars, Corvette, Ford Thunderbird, Mustang, GM intermediates, Nova and Pontiac Fiero all handle wonderfully and much better than in their stock configurations, all without the unnecessary expense of lowering springs.
This is what Herb Adams has to say about lowering springs -
"Many of the other suspension part companies want to sell you new springs. Obviously, this is because they make a profit doing so. Unfortunately you don't need new springs, so we think this is a waste of your money. A few years ago these people were selling high-rate springs under the pretense that they improved handling. Now that the truth has come out, these companies now want to sell you springs to lower your car. Before you invest in springs to lower your car, you should be aware that your chances of success are much better if you simply cut your existing springs. All springs take a certain amount of permanent set after they are installed. (Note that new cars sitting in the showroom are higher than the same models with only a few thousand miles on them). This change in height is caused by the inevitable loss in load that any new spring experiences. If you put new springs on your car, they will settle as much as an inch within the first few months. Obviously, if your car was the correct height when you installed the new springs, it will be too low after a few months.
This is why we recommend you cut the existing springs and save the cost of new springs. The result will almost certainly be better. Your car's existing springs have already taken a permanent set, so you know where they will end up. If you want to lower your car, you can cut your existing springs and achieve the ride height you want with one operation. Some spring peddlers want you to trim the spring to height as required, (read the fine print). This means you might need to remove and cut the springs several times before you get the correct ride height -- or you might trim too far and have to buy another set of springs".
