I have the barton 2-post and it was a tremendous improvement. However, it is buzzy as hell inside. I have dynomat i intend to install. however, as easy as it is to change I may consider trying the steeda w/ the stiffer bushing. I can't see that one being any louder...
I drive w/ radio off and windows down regularly. so I'm more aware of such noises etc.

 

Steeda has 2 versions with different durrometer. The harder durometer will increase nvh. It buzzes like your barton, but not that bad though.

 

I have the Steeda and used the harder (black) bushing. NVH is minimal with no buzzing on mine. In 5th and 6th gear there is no noise at all. I also have the Steeda shifter. I'm very pleased with both.