On a performance spring, typicallly they are progressive in nature. This means they get stiffer the more you compress them, or the harder you push, the harder they push back. I absolutely could not believe the difference it made on the bug when I put the sporty springs on there(Of course, replacing 25 year old springs can't help but improve your handling), it out handled a 240 Z on a rally I did afew weeks ago. Get new shocks when you get the springs, you will be happy you did.