Notifier,
While a CHMSL is a good idea, you should also consider replacing the incandescent bulbs in the brake lights with LEDs. Doing this is easy and does not change the appearance at all. Best of all it gives the cars behind you an extra 200ms of response time (since incandescent takes longer to turn on and LED's "instant on" gets the drivers attention fast too). This may not seem like much, but at freeway speeds, that's a full car length! I have the GM LED CHMSL and LED brake lights for maximum safety. If you go with the older CHMSL one, see if you can swap out the bulbs for LED. Same appearance on the outside, but all the safety benefits of LED!

Some "fun" reading on LED brake lights brought to you by HP:
http://chemlinks.beloit.edu/BlueLigh...p/an1155-3.pdf

As for how I mounted my CHMSL, I simply glued it in place using black calking (same stuff I used to seal the roof). It was meant as a temporary thing, but 7 years later it's still holding strong. I also painted the wiring black and simply wrapped down the front of the louver and back. Yes it's visible from the outside, but you really have to look at it. I did it this way as I didn't want to drill into the louvers. I'll see if I can get some pictures later today or tomorrow.