My Porsche has terrible road noise - Please HELP!

Hi, I have a 2002 Porsche Boxster S with 62,000 miles. My car has 18" tires and the rim sizes are different from front to back.

I just had my rear tires (265/35/ZR18) replaced with a new set of the identical tires I had before (B.F. Goodrich g-force sport). I have been going to the same tire shop for years, but they closed down so I went to a Tire Rack recommended installer near my home to install these. They had good ratings and are part of a national chain. After the tires were replaced, my car began making horrible road noise. I thought it may have been the tires, so we replaced them, but nothing changed.

When the tires were installed, the car was aligned and the tires balanced and it seems to ride OK except for some very minor shaking at 80+ MPH. However, the road noise is unbearable. If the top is up, the road noise is so loud that you cannot have a conversation in the vehicle, but when the top is down, it is not noticeable. The noise also increases dramatically as the speed increases.

Can you help me figure out what is wrong? Could this be caused by bent rims? Any ideas on the cause and suggestions on how to fix would be greatly appreciated.

Thanks (donation was sent)