Installing the Coastal XM in TEN MINUTES

~10 minutes if you've watched the process, 30 if you haven't, and 60 if you drop the bolt that holds the computer.

Tools/parts: 10mm socket and long extension, flat screwdriver, diag cutters, cable ties, double-stick foam tape, band-aid

1. Remove lower glove box and pass side left A/C vent panel -- both are simply pull-outs with plastic friction fasteners.
2. Remove the 10mm bolt holding computer and pull it free, twisting to one side to gain access to the rear of radio (trickiest part). I rotated the assembly and moved it several inches to the right, completely out of the way.
3. Lever up tiny gray panel at the smallest pass side forward window, and snip off forwardleftmost 1/4" of plastic to create a pass-through.
4. Put the antenna on the dash, all the way forward, attached with doublestick.
5. Run antenna wire through hole created in (3) and down to glove box, and replace the gray plastic panel - dress the double cable neatly. NEVER LET THIS CABLE CRIMP OR BIND!
6. Put XM radio in the glove box, in the slot once used by Prius manual, connectors up, and plug in all three cables. Use folded maps to keep XM module from rattling.
7. Run the heavy cable from XM unit to rear of radio (insert clip-down, next to existing cable). I bound up the surplus and tucked it neatly away below the radio (plenty of room).
8. Dress all wires neatly and bundle them, tucking away the surplus and tying down with cable ties. I snipped away a bit of plastic from the dash where it drops down to the top of the bottom glove box to give the wires some clearance.
9. Replace computer, a/c panel, glove box, etc.
That's it!

The swept back angle of the windshield lets the antenna "see" the satellite in most cases without interference from the roof even if it's not on top of the car, though I'm in San Diego and that may not be valid in more northern latitudes. Signal strength seems fine even without a metal base. In built-up urban areas like mine, XM has terrestrial repeaters and reception is fine even if the antenna does not have a clear view of the satellite.

TO OPTIMIZE THIS INSTALLATION:
a. If anyone can figure out how to get under the dash *easily*, let's put the antenna there and make the wiring completely disappear. Also, that will permit the antenna to move forward a few inches, increasing coverage.
b. In putting the antenna under the dash, a grounded steel plate under it, perhaps 6"x6", will theoretically improve reception.

Henry