Seriously you guys. If you are considering using the OEM gps from Garmin, consider buying the Glisson antenna from GPSgeek.com. It is a direct replacement for the ga27c from Garmin for $45.00 cheaper. I have used Garmin products in the past (I have an iQue 3600 and etrex Legend) and I've found their antennas way overpriced.
Just my thoughts.