I agree with Audiolabyrinth.
I have the GTX-D with the outlet frame. The outlet frame itself made a dramatic difference. So I thought the cover was an afterthought (and only for aesthetics).
I just installed the Furutech cover and I'm stunned at the increase in performance. There is less smearing of the sound so it comes across as an increase in resolution, clarity and smoothness. The leading edge attack is faster and overall it solidifies the sound. Sounds so crazy I was hesitant to post this.
I have the GTX-D with the outlet frame. The outlet frame itself made a dramatic difference. So I thought the cover was an afterthought (and only for aesthetics).
I just installed the Furutech cover and I'm stunned at the increase in performance. There is less smearing of the sound so it comes across as an increase in resolution, clarity and smoothness. The leading edge attack is faster and overall it solidifies the sound. Sounds so crazy I was hesitant to post this.