Oh go on then. Funny you should mention the intake manifold.
The C270 they have is a diesel... and it (like BMW*) had swirl flaps, and of course an EGR setup. The flaps basically come loose, and in the case of the Mercs, generally cause boost leaks and get eroded by the nasty exhaust passing over from the EGR, which also makes a horrendous mess of the entire intake manifold, choking it up severely. Or, in the case of this one, as well as some of them coming loose and having been worn away, and the nastiness EGR mess I've ever seen, the linkage jammed up causing it to break off the motor. Solution is remove manifold, clean inside, remove all flaps and blank them off, fit some bypasses to the wiring to fool the ECU into thinking the flap motor and EGR valves are all still there. Simple.
*I suppose the only thing this has over BMW designs, is that in a BMW, the swirl flaps are directly over the intake valves, so if/when they drop off, the engine eats them, goodbye engine.
Except the intake manifold is like a basket shape, and has all manner of crap fitted inside it. Fuel heat exchanger, fuel filter, PAS reservoir, countless hoses... oh, and the wiring loom to the starter motor and oil level sensor pass THROUGH the manifold. So as well as removing all the crap on top, you then have to jack the car up, remove the whole massive undertray, to unplug the damned oil sensor.
Then it still won't come out, because the EGR manifold wraps around the intake manifold. So you have to take off the entire fuel rail, then drop all the coolant and remove the thermostat housing. Then you can lift the manifold out intake runner ports first, clean, de-flap, reassemble.
*Unlike the Merc, on the BMW, the intake manifold is on the top of the engine, and bar removing the fuel rail, is comparatively piss-easy to remove.
Then spend a further three days retracing everything trying to work out why the damned thing keeps going into limp mode as soon as you plant your foot bar one period of about 10 minutes of normal operation, only to find that no, it wasn't either of the flap/EGR bypasses, but a broken wire inside the plug for the boost pressure sensor that you didn't even go anywhere near, but decided to make a break for freedom right as you were messing around with the rest of the engine. And of course, no normal OBD reader would read that fault. Only bit of luck was a local independent that didn't charge me for plugging in, thankfully.
Like I said... smoothest driving car I've ever driven, would make a superb commuter, and the 5 cylinder diesel sounds good and goes pretty well. But I just couldn't own something with such ridiculous design as that engine. Somewhere buried on the other side is the turbo... you can't even see it.
Also - that's a really nice looking L322. Being a 2004, has it had a facelift done at some point, or was 2004 sort of the earliest facelift models that were still BMW based?