Finally got my Scangauge II mounted, but it's not fully calibrated yet (haven't been to the pump for a fill-up and initial set). Here are some photos and install notes.
I solved the A-pillar cover removal problem by not needing to remove it at all. Instead I found a flat black ethernet cable that can be easily slid into the narrow slot between the pillar plastic & windshield glass. Even if should it stick out a bit for you, it is invisible against the black enamel coating around the edge of the glass. I found this cable at Cyberguys
where I buy a lot of computer stuff. It's part #119-6410, $4.45. I also got an RJ45 coupler (#180-0500, $0.85).
The cable is 10' long, about 5/16" wide and flatter than a phone line. Even allowing extra inches where it comes out from between the glass and the panel above the mirror (can be pushed back back under the panel once the Scangauge is mounted), I have more than a foot left at the other end below the OBD port where I coupled to the SG cable & stowed the excess.
Remove all the screws (you'll need two sizes of Torx drivers) holding the "overhead control panel" plastic (this means removing the sunvisors too). Loosen the back end of the panel by getting your fingertips between the headliner and plastic at the extreme right and left ends and bending the panel end out towards the rear of the car. There's only a little tab of plastic clipping the panel to the piece over the door. Push the panel forward about an inch and it will drop down held up only by the electrical wires feeding the domelight and passenger airbag monitor.
Making sure I had enough extra cable coming out right above the mirror, I taped the flat ethernet cable in a few spots along the steel frame leading it over to the A-pillar. I removed the screw in the over-door covering at this point and put the cable behind it, then replaced the screw, figuring this would retain the cable in place at the upper end of the A-pillar. You can replace the overhead control panel now, fitting in the front edge first which has four tabs that go into slots in the metal frame.
The cable slips easily in the small space between windshield and A-pillar. If the fit between glass and plastic on your car doesn't hold the cable in place, wedge it in with a narrow strip of cardboard, plastic or perhaps a dab or two of clear plastic cement.
At the lower end go all the way out to end of the pillar cover before bringing the cable back in the crack between dash and door edge.
I removed the few screws (including the one fastening the OBD port shrouding) holding the bottom edge of the padded dash so I could push the cable in behind where it wouldn't fall back out, then replaced the screws.
Plug in the cable that came with the Scangauge into the D-shaped OBD jack, and loop it around so it comes out where your ethernet cable comes out (past the last screw). Connect your two cables with the coupler and coil up the excess. There is room behind the plastic shrouding just to the right of the accelerator pedal to store the coiled cables.
I removed the screw in the side of the plastic just to the right of the pedal. and inserted a piece of thin metal flat bar about 4" long, with a hole near the end for the screw to pass thru, to serve as a retainer behind which to tuck the cabling. You can easily remove your Scangauge and its cable to use in another vehicle, without disturbing any of the ethernet cable.
I put both pieces of velcro that came with the SG on the top of the unit, plugged in the ethernet cable into the back port, and adhered it right above the mirror, moved forward enough so that it is right up tight against the mirror mount. This gives me a little extra insurance if I press the buttons too hard, as it's not just the velcro I'm pushing against.
Sorry I didn't get a picture of the upper panel off to put here...