I have my GPS and XM antennas mounted IN my dash (on steel strut the crosses over radio, so its only covered by the cars plastic radio/console trim), not visible at all. I do loose a lot of signal strength doing this, but with a convertible, I have few options.
Having the GPS mounted that way is less of a problem than the XM one, GPS can loose signal here and there and still keep you on course with the gyro and speed sense. The XM is more of a problem, basicly any other obstruction (big truck, tree, tall buildings, etc...) and it cuts out right away. I canceled my XM, not because of thi