Are you saying that there was no (cabin, correct??) filter? Hmmm, now that's interesting... I'm assuming Bosch gave you the wrong directions...
The filter is under the dash, passenger side, above the passenger's feet. If you look under there, you should see a plastic panel with holes in it (for recirc). There are 3 screws that hold this in... they are in a line below the glove box (but still under the dash). Once you have removed that panel, there should be a sliding panel thing (white i think). Not sure from there, I don't really remember, but I'm sure you can figure it out. Anyway, good luck and let me know if you have any other questions. BTW, did you get a charcoal filter?
As for the meeting... I was sitting at Breuggers Bagles today in that same table and was wondering the same thing. We need to do this soon, I'm dying to see those 500E's! TTY soon.
2006 E350 w/ 155k miles (Daily Driver)
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)