Ah, but a closer look would reveal it's NOT NA (if, in this case, "NA" means Normally Aspirated). The photo of the engine shows the tell-tale u-shaped tube below the air filter housing, indicating the presence of a turbo. Also, the EGR can be seen, and it has the later cruise control, further evidence that this engine is at least a few years newer than the rest of the car.
Add to that, MB never made a LWB 300D. (I'm pretty sure of that, anyway....) In Europe, limos were considered working vehicles whose purpose was to make a profit. The lower initial cost and on-going maintenance were valued more than the driver's comfort or convenience. So, it was probably originally a 240D LWB, now with an OM617A dropped in. Which, would make for a very interesting drive, provided it was done correctly....
Mark in Lakewood, CO
To: diesel_mercedes@yahoogroups.com
From: audiolaw@aol.com
Date: Thu, 13 Jan 2011 19:05:29 -0500
Subject: Re: [diesel_mercedes] Re: 300DL W-123 Limo
It's a stick! Wonder what a NA stick limo would be like.