i'm about to jump for this equipment

"sandpiper" reciever is what i've heard it referred to as
http://cgi.ebay.com/OEM-NMEA-GPS-Mod...QQcmdZViewItem

active antenna, the tiny square one.
http://www.mobilegpsonline.com/gps_antenna.php

has anyone ran the reciever thru a serial-usb converter? i have one serial port on my laptop, which will be used for XM. i need to get a gps that will work for usb. this is the only issue holding me back on this.

as far as mounting the antenna, my plan is to mount it right behind my rearview mirror. i have the top-edge "sun-tint" in the car though, will that effect it? I'm not sure how "metallic" it is, since its integrated into the glass. also, will it be fine mounted "upside down"?

much appreciated, thanks