Also, wipe the "probe" end off - there was a guy here who theorized that metal flakes and etc. on the probe were confusing the sensor inside.

You may be wasting your time looking locally - try autohaus.com and germanautosupply.com (as well as Amazon - but they steal your identity and kill butterflies).

You want a Bosch 0 261 210 170

The Mercedes number is 003 153 27 28

Use either of those numbers in a search on those sites and you'll be fine - don't let it bother you that it won't mention fitting a Crossfire.