Broke this out as a separate post for ease of finding:

2005-6 e320 CDIs had a Sirius Sat radio option available installed by MB or dealer when new.

The "bug" on back lid is post-VPC Sirius Antenna I believe. If vehicles had Sirius Sat. Radio added at dealership, this is where the Antenna was mounted and necessitated a hole being drilled in aluminum trunk lid

VPC (Vehicle Processing Center) prepared vehicles had the system added before being sent to dealers. I believe Mercedes mechanics added the Antenna to the roof in front of the communication antenna.

For vehicles without Sirius, you can install a MB command driven system which necessitates finding a MB Sirius module. These can only be found used I believe (~$100 on eBay for used one). The 2005 CDI was pre-wired for it I believe and the 2006 may not have been. You then have to install the module, an Antenna and the command unit needs to be programmed to recognize the module (no plug and play).

Easy aftermarket install

For my vehicle, I think I will bypass the MB Sirius system and install a stand alone system plugged into the Aux 1/8' jack in glove compartment, powered from fuse box on left of dash next to driver and place a small antenna near front window in center.

Here is a site describing what I am thinking about as done to a W211 wagon:

How To: Install a Satellite Car Radio - I

The link is from 2009, is this still the easiest (means best to me) way to do it?

There are stand lone units with lifetime subscription for the unit available on eBay for around $300

__________________
-- Chris

'95 E300, 216k miles, Silver Surfer
'05 E320 CDI, 138k miles
'07 S550 4matic, 69k miles

Gone but not forgotten:

'76 300D, 350k miles?, SOLD in 1995
'75 240D, 300k miles, SOLD in 1991