It will definitely be a pain, but I may try to mount the probe into the capped hole and take readings there as well. That's a thin sheet metal cap and I'll need to figure out how to attach a 1/8" NPT threaded hole for the probe there. Zeitgeist has the same car as me, with the EGT probe in the same location, and he's seeing much lower EGT's but he has a front-mount intercooler, and no water injection. I was wondering if my readings were a little high since the probe is so close to the exhaust valve, but his data seems to indicate otherwise. (??)
BTW, I've got a detailed thread on this topic over on the Mercedes forum with some photos of the gauges, including a photo of the EGT reading at ~1500F, over here:
http://buymbparts.com/forum/showthre...5&page=2&pp=20