As for a better installation of a good antenna and trying to reduce noise...

You might also want to check and see that (if you have one) your hood over your engine is grounded. I fought for two years looking for ignition noise in my radios in an old car I had. After going to an automotive electric shop and asking their suggestions (they had none) I asked a lot of my ham friends out there and one random question that I heard was "Is your hood grounded?"

After looking and seeing that it wasn't, a quick addition of a small piece of woven ground strap between the hood and the chassis fixed the problem instantly.

In my new vehicle when I went to start the installation process of putting the radios in it, that was the first thing I checked. It already had one!

-K