My antenna on my VW Jetta weathered away leaving a small stub sticking out of my roof. The antenna cover is a great improvement and even improves the reception on the radio, especially considering that hardly anything was left of the original antenna.
My old antenna broke and I needed something to replace it. This threaded right on and the 3M double sided tape worked great. Honestly, the radio worked even with the antenna broken so I can't speak for how much it helps range but I can get my car washed now without water getting into the antenna. Totally worth it and easy to install.