I just did this mod on my wife's '06 2.5i. Unlike the Ursalia mod, I just popped the middle grill out, unscrewed the back piece and used a razor knife to carve out access to the badge (being careful to not go too deep and scratch it).
After getting to the foam adhesive back, I pushed the badge off of the chrome surround, and cut all of the remaining black ABS plastic, leaving only the chrome tabs.
I used acetone and took off the factory paint, leaving the chrome stars.
I used TESTORS model paint; Boyd Kandy Purple (this is a translucent enamel, perfect for this application). I tried to find an STi pink, but the purple was the closest and actually looks pretty cool.
I used an LED light strip, cut down to 9 LED. I dremeled the back piece of the grill down to accept the strip (the piece behind the badge), epoxied it in and used contact cement and heavy duty aluminum foil for a reflector (the LED strip is "front firing", so it may not matter, but I figured the more light the better). The 5 watt side marker light used by another poster may be brighter and may be something I do in the future; I had an extra LED strip handy, so it was used.
I epoxied the badge to the chrome tabs and put it all back together.
I wired it to the parking light lead and it looks great!
It took a little over 90 minutes from start to finish, and now we'll wait and see if she gets popped for illegal front lights by the California Highway Patrol (I had blue halo's around the foglights on my Grand Cherokee SRT8, and that resulted in a $35.00 fix-it ticket).
I will post pics as soon as possible.