I have a 01 Cobra with Eibach springs and took the isolators out. They squeeked so bad with them in. Now there is no noise and the ride seems actually better. No harshness or anything. I have squeeks coming from the back when I added the poly urethane ones. I am planning on taking them out tonight to get rid of those squeeks as well. If you drive your car daily, I would say leave them in though. The rain, snow, salt and sand may make them rust quicker in the lower pocket?