Scraping noise when it's cold?
 

Hey guys,

My car has been making some scraping noise both in the front and rear when going over slight bumps at low speed. Funny thing is it rarely makes that noise when going over big bumps at high speed. It sounds like the engine splash shield scraping the road, but there is nothing wrong with the shield. The noise was noticeable more often about a week after I have installed a new catback exhaust, but it was also the same time when the temperature started to drop. When it got warmer during the day, the noise happened less, sometimes disappeared. The exhaust looks very sturdy, so I thought the low temp must exacerbate the noise. A couple threads here suggest that the shock bushings or the strut mounts may have gone bad. It kinda makes sense to me since I have had Swift springs on for about 3-4k miles. Some people suggest that the Hotchikis sway bars might need to re-lub, but it doesn't sound squishy though.

What do you you guys think? Please give me your opinion. Thanks.