I ended up adding the equavalent of stage 2 sound reduction. Now I know why the ranger said my 1.5 is the quietest Roadster he has driven. When I got the sound reduction kit the Roadster was stripped apart. So before reassembly I purchased 4 Dynamat kits and carefully covered the passinger tub and then inside of the doors. Then we added the sound reduction on top of the Dynamat. But still with the wind noise the Roadster is still not a quiet car.
Dynamat is a sound reduction pad. It is about 1/8" thick and sticks like tape, and is supposed to absorb noise. I measured about a 6 db reduction in noise. I believe a 3 db increase is considered twice as loud.