Short or long port, boosted or not, high RPM or low RPM, it's all about the
approach to the valves. There is a reason M.B. spent time, effort, and money to research, create, retool for and put into production the raised port heads to replace the first gen. M104 heads when the first gen M104s were
only three friggin years old. There is a reason all newer performance oriented engine's ports are placed high and getting higher compared to the "good old days". Take a look at the "new" "Coyote" V-8 Ford is releasing as we speak.
Interestingly, The M119, which is a year older, went from CIS-E to LH to Motronic, from 1989 through 1998, a ten year run, with no change in it's head or port design. Car companies don't spend money unless they are forced to by competition or regulation or both. Old man Ford finally replaced the Model T only because competition forced him to. They'd still be selling those things today if they could have gotten away with it. M.B. replaced that only three year old head for a reason and it wasn't just for emissions.
The "new" Coyote V-8, which, despite what Ford would have you believe, is really just a new set of heads on the old "Mod" engine, is being rushed into production only because the Mustang is now, once again, the slowest pony car out there. Just like in the old days when they created another "new" pair of engines, the Boss and the Cleveland, which was again, basically just a new set of heads, to get themselves competitive again. It's not something any car company likes to do unless they have to.
You've got to remember that Lexus came out of nowhere in 1989 and almost immediately began causing serious misery to M.B. and BMW.
Again, the older head is shooting the intake charge across the valves, the later head is shooting the charge down through the valves. It's not just about how much air and fuel you can flow through the ports. It's also about what kind of condition the mixture is in when it gets inside the combustion chamber. Slamming the fuel/air mixture into that far port wall can cause some of the fuel to drop out of suspension leaving you with a poorly mixed, not very homogeneous mixture. This also appears to me to be another issue that M.B. was trying to address with the updated head. Now with a nice homogeneous mixture you have greater fuel efficiency, greater power, and cleaner emissions which I believe somebody said was what the engineering paper said was M.B.'s stated goals for the 2nd gen M104. So even if that later head doesn't flow as well as the earlier head does, it might still make more power anyway. (But for the record, I still think the later head does flow more because, again, the charge is being shot down through the valves, not across them. This means the charge has full access to all of the valve area, not just some of it.)
I'm sure many of the answers we seek are in that German engineering paper. We need a translation!
Regarding the intakes, are we forgetting that the later intake has a valve that switches the intake between a low RPM torque mode and a high RPM power mode?
And yes, I agree that the flow tests should be performed with the intakes in place. Just be sure to test the later intake in both of it's modes.
What you have here is two guys telling you the later engine is better. One guy who owns one, and another guy who just had his 400E's butt kicked by one at our most recent dragstrip day.
Regards, Eric