I am a subscriber to the Mercedes Heritage Centre, and the latest newsletter talks in some detail about the 300SE Coupe/Cabriolet. Here are the details:
http://www.mercedesheritage.com/2012/300se/
I found this feature to be excellent reading as I do know a fair bit about the air suspended models, including this 300SE Coupe - Not the one featured in the article. It's a very frank assessment - in fact, almost too much so. I disagree with their assessment of the airsuspension foibles. Once the system is sorted, it's ultra reliable. Suspension valves can be sourced locally, and Air Bags, whilst expensive, should comfortably last five to six years.
That engine though - it is a work of art, and expensive. Totally unique in design, with a flat head and single overhead camshaft, and the combustion chambers are contained within the shape of the piston crown - like in, guess what ? The ROVER 6 cylinder engine that had its origins back in 1948 and culminated in its final form in 1967 - almost twenty years. Anyway, this 300 Benz engine is an all alloy affair, and actually quite noisy in operation. They reckoned you could always HEAR them coming. I used to have a Finnie type 300SEL Sedan, with that very same engine. At slow speeds it was horrible, at high speeds it turned into a jewel of an engine. The water pump was located at the right hand side of the engine block, and driven by a humongous flexibly coupled generator. On some models (later), there was an oil temperature controlled engine fan. I can tell you, that was quite an engine - I just wish I could illustrate with photos. Hope you guys enjoy my ramblings. Regards Styria