I finally installed the optional LED for the MDC last night and have to say that overall I like it. I have three nit-picky issues with it, but overall I'm happy I finally got it!
Issue 1: The cable length is just a
wee bit short; especially after routing around inside the speedometer casing, down the back and into the console. I did it, and there's enough slack cable to follow the path of the other cables when installed. But if I ever need to take the speedo off again I'll probably have to unplug the line from the unit first. This is partially because I chose to put the MDC control box inside the console near the battery well on the
passenger side. If you put it on the
driver side, or up behind the OBD connector, you'll be better off.
Issue 2: The LED isn't
quite as bright as the rest of the console LEDs. It's still quite visible, even in bright sunlight with the roof down, but it's a little less
intense than the factory LEDs.
When it's red, it's almost the same intensity as the factory orange lights. Yellow and green are slightly dimmer, and distinguishing yellow from green in daylight can be difficult. Happily only programming uses yellow, and telling red (govern) from green (cruise) is easy, even in bright daylight.
Issue 3: It blinks like a rabid weasel on crack!

You unlock the car, it blinks. You turn on the car, it blinks faster. You engage the parking break, it blinks. You turn the car off, it blinks until the
console relay goes off (that loud click you hear about 20 seconds after taking the key out...) You're cruising/governing and over/under shoot, it blinks.
Not that blinking is bad, but in all but the last case it's doing a
tri-color blink, which makes it stick out from everything else on the console. So even if maintenance people don't notice the stalk, they'll definitely notice that blinking tri-color icon on the dash now.
Like I said though, over all it's great to have. I may take it all apart again and re-do some of the wiring later. Maybe I'll move where the box is located, and/or put a removable jumper block in line on the back of the speedo? But for now, it works great and it's fun to be able to see what it's up to.