I have not tugged on it myself, but my brother in law who is my dealer tech, grabbed hold and pulled it off just to show me what was underneath. I didn't feel how tough it was with my own hands, but I watched him tug and watched it come off.
Once it was off I was totally amazed, mostly by the size of the mass airflow sensor. It is HUGE! It is much bigger than the one on my 5.7 liter Vette. You joke about the 780 Holley, but this engine could probably handle it. That's one of the keys to the incredible power these little hummers produce.
A few weeks after I got my C240, my brother in law called and told me that he had one of these engines apart and asked if I wanted to come by and look. It actually was a V8 version of the same engine, only difference is two extra holes.
This engine is an absolute masterpiece. It has such incredible technology inside it's amazing. To start with it has cross bolted mains, roller cam, two spark plugs that fire a certain number of crankshaft degrees apart so that there is no piston rocking, cold cracked connecting rod technology, etc. These engines have proven out very reliable in the five years that they've been out. The only reason that one was apart is that it was in a wreck and lost oil before being shut down.
Much of the technology in these engines is Formula One stuff of about ten or twelve years ago. If you ever have a chance to see one completely apart, don't miss the opportunity.
I hesitate to tell you to just tug harder, because John may have known just where to tug or something. It sure looked easy when he did it though.