I have a sedan bud...and you would be suprised.
if your coupe is manual, i would get a system, and say screw the noise. turn up the radio, get the TripleTred's and have a blast!
But as far as silence goes, absolutely, hands down, the most SILENT tire i have ever had:
Tire Details - Discount Tire Direct
The Falken Ziex ZE-512. Hands down best traction, wet or dry, and quietest ride of any tire i have had...and i have had alot...and they are cheap...
but be ready to buy a set a year or MORE, cause they wear very fast, and if you drive spirited, they wear stupid fast. A friend of mine had them on his Lexus IS300 manual, his set lasted 9 months...but for $65 a piece and a silent ride with that kind of traction, he wasnt complaining.