GPS Antenna location

These are my questions. Please feel free to answer any you know anything about.

1. Where is the OEM GPS antenna installed?

2. If one wants to add an aftermarket (i.e. Garmin) GPS with an external antenna, is there a place in the dash to put the antenna part with physical dimensions: 1.5â€(W) x 1.76â€(L) x .5â€. On a non-Nav Prius, is the space where the OEM GPS antenna would be available? Any where else inside the instrument panel that would fit AND get reception?

3. The plastic instrument panel top cover is thin enough not to be a problem blocking reception? Would I be correct that if it's thin enough for the OEM antenna, would also be thin enough for the Garmin add on antennas?

4. From whereever that antenna might be installed under that top plastic instrument cover, how hard would it be to run a wire behind the MFD and out through a hole drilled in the back of the CD holder (rectangular box you open the smoke colored plastic door to get to that appears for some reason to be called the "stereo opening cover" in the Prius 2005 repair manual.)

5. Eddie Bell (who I'm sorry to report recently passed away) created an XM radio install PDF that shows the CD holder attached to left / right radio brackets. Does anyone know if you can remove the CD holder by somehow getting to those screws without having to go through the entire procedure up to pg. 19 of his install PDF?

6. What's behind the CD Holder and would it be safe to CAREFULLY drill a hole in the back of it while it's still attached to the left / right brackets and somehow then get the antenna wire through that hole (since I'll have already taken apart as much of the instrument panel as necessary to have installed the antenna in 1-3 above?)