Don't feel bad....it's not the only MB design flaw! While replacing spark plugs on my '92 500SEL the other day (not a simple job I found out!) I discovered that on #8 (I think...drivers side, rear-most) that they placed two rigid gas lines to the FI precisely on top of that plug....no possible way to get it out without disconnecting them, with the resulting air leaks into the fuel system! So....MB is human after all!

__________________
1996 SL320 97K miles
1996 C220 130k miles
1992 500SEL 170k miles <---sold
1986 300E 216k miles <---sold