I have a little clunk noise coming from rear of my 04 civic si after installed Progress front and rear sway bars. Did I not have everything tight enough, or is this normal. All the bolts were fastened with impact tools. Please help!

 

this is completely normal. When i had an ep and the progress bar mine would clank or rub on the exhasut when i made a left bend or turn. Its just because the bars are bigger and not the same shape as the oem bars.

 

I have a progress bar on my 93 Civic. It was fine, no rubbing or noises from the rear. Then I changed the header and cat, which pushed the exhaust rearward. All of a sudden, the exhaust was hitting the bar. I tried exhaust wrap, but it eventually wore through it. So I had to get the part of the exhaust that goes over the rear control arm redone. Problem solved.

I wouldn't ignore it. Two metal surfaces vibrating against each other... eventually the softer metal exhaust pipe is going to wear a hole. Also the protective surface of the swaybar is going to chip off exposing it to corrosion. Not to mention the annoying sound.