I've still only got 370 miles on mine (LOUSY Pa. weather since I bought my car!) and so I'm still in the breakin period and haven't beenn driving at 70mph yet. BUT, I have already heard a bit of a rattle up in the dashboard of mine even at lower speeds (although to be honest, it isn't bothering me because it doesn't sound like anything important and I have 3 more years of warranty in case it is).

And my mom's 3-month-old 1000 mi Buick LaCrosse has a similar road noise (which since she has a 4 year bumper-to-bumper I'm even less concerned about hers).

But yeah, there may be something here that's a "characteristic" of the Challenger...???...