On a Duster, won't work on a Dart. Also, you're car is sitting up pretty high in the back, so that makes the clearance on the quarter less important.
I have 295's on mine as well, but mine are 295/35/18's. With the car lower I trimmed the quarter lips to keep things from rubbing. Even mine sits up a little higher than I would like, but the springs don't have many miles on them so they may settle in a bit still.