John (49er), In the photo of your 250sl engine compartment that Artur posted, On the top rear left (drivers) side is an engineering tag (rectangular). Do you happen to remember what it said? I had an almost completely destroyed label in that exact location. All that was left was some off-white or yellow remnants, red font, and the outline. The size matches the "Achtung" spark plug warning sticker that I have seen before but cant be sure.