I used the projected fog lamps that came stock off a MK3 Jetta GLX VR6. No, not my old car, but my little brother's car as he was donating it. His car had seen better days so I took what I needed before it was towed away.
Eye'ing the MK3 fogs and a spare set of stock B5 S4 fogs I had, there looked to be some possibility to making it work. Obviously I'm looking for simple functionality because the 3000k HID's I have in my stock fogs now just weren't being used to their full potential.
The APR Boost Gauge uses a standard incandescent 194 wedge bulb which does not continue the overall theme of the red interior lights. I replaced the incandescent light bulb with a red 194 wedge LED bulb from Superbrightleds.com. I also put the same red LED bulbs in the foot lights under the dash for the driver and passenger seats. Gives the floor nice red glow.
I also replace the 4 BA9 map light bulbs (2 front and 2 back) to a cool white LED bulb that I also got from Superbrightleds.com. This matches the color the current dome lights as show in February 2008 post below. They are surprising bright but not blinding when you are driving.
I then replaced the 4 incandescent 194 wedge bulbs in the 3rd brake light in the rear window with red LEDs from Superbrightleds.com. For one, the LEDs are brighter and activate faster then incandescent bulbs allowing drivers behind me to see that I am braking a split second faster. Every seconds counts...
After replacing the 3rd brake light I ran into a problem with the bulb out warning displaying in the dash. After doing some research and reading suggestions from many online forums I order a load resister from superbrightleds.com and got the bulb out warning gone in a few mins.