Got the O2 sensor (bosch) at a local auto parts store (it was in stock) for $120. Found the MAF (bosch) on eBay for $145; I had to pay $10 shipping, so it was really $275. There are two different MAF parts for the older model mercedes; the newer MAF model is more expensive and requires adjustments to the computer system. I bought the original (older) one.

Regards,
Steve Darcy
1993 300TE