When I put in my 4-cylinder springs, I left the isolators out because the springs are so tall it was hard to get them in with the isolators on. But the car sat so low that the tires rubbed inside the wheel well. Of course, the 4-cylinder springs sit the front of the car real low to begin with. I had to put the isolators back in. But I had no noise from the springs making direct contact with the spring perch. Your car will sit 1/2" or so lower if you remove the isolator.