well for starters turn the flange on the front connection so that it's not up and down, that isn't helping the scraping thing any. After that loosen the rear connections, jack up the piping and then retighten. You'll gain atleast a few inches that way. My car had the exact same midpipe/catback on it last summer and my cars lowered ~1.5". At first i'd scrape on mild bumps or crowned roads. After I did what I just told you to do, I never scraped again over the same bumps.