At 20k miles I replaced the stock Conti's with BFGoodrich tires that came off a new Mercedes roadster. They were wider (275's) and BOY are they loud. But then again, the car was loud on the highway before. Oh well, these stick like a dream. But it sounds like you might have other issues. Just wanted to put in my 2cents.

And Inferno- could you add me to the Texas list? I'm up here in Lubbock.