just fyi. the mercedes mod only cost $16.88 shipped off ebay and I didnt have to pull the housing out to do it. just popped the plug out after removing the interior panel and used one of the small precision flat blades and an 8mm socket to bolt the ground wire to one of the tail housing bolts. you literally pop one wire out of the tail harness and click it into the middle of the mercedes harness and swap your bulb and done.

much easier than fiddling with solder and such and its done forever. but thats just me.