Just 150 miles on my 2006 GT with 18" B.F. Goodrich tires, and it seems there's a lot of tire noise going over sewer covers, cracks in the pavement, etc. The noise seems particularly pronounced at slower speeds, and seems loudest from the right front tire. The left tires seem quieter. It's almost like something is loose, but it's not a metallic sound - more like a thump. The tires are properly inflated, and there's nothing I can find that's loose in the trunk or under the hood, like the battery. It may just be tire noise that I'm not use to, because it seems to quiet down at higher speeds, when redial tires are performing at their best. Any Ideas? I may ask the dealer to drive another GT for comparison.