I have had very good luck with this web supplier for two different vehicles:

   http://www.antennamastsrus.com/

The quality of the $27.95 stainless antenna mast I purchased for my 3000GT
was identical to what I replaced.  Interestingly, my local dealer wanted 4x
the price I paid through this place, but told me they needed to order it
from "their warehouse" in Milwaukee, WI.  Bridgewood Motorsports is located
not far from there in Manitowoc, WI.  I speculate they were going to buy the
same mast and just charge me a whole lot more.

Good luck.

      Bob