I was going to swap out my Conti DWS to Pilot sport A/S plus but I found this issue is quite common with this tire. My boss has the same problem with an 2006 Acura TL also, the tires are 2 years old and has the same problem. Try the Bridgetone 970 AS if it where me. Conti DWS I've had a lot of vibration issues now I'm stuck with them, my dealer only wanted to put me into the Michelin A/S for an extra 500.00 on top of the 800 i already paid. Good luck Tire warranty's they are almost impossible to process.

 

I had a similar problem with those same tires. They came with a set of wheels I bought 2 cars ago and I'll never go near 'em again.

 

I'm running the DWS at a pressure between 37-38psi to avoid flat spotting. Seems to be doing the trick for me.

 

That is actually very common with those tires and any other Michelin's. I am not at all surprised to see that. The other problem with that tire is the centers wear out faster than the rest of the tire because it is a softer compound. Great tire, just don't last very long.