again, I do work at BMW and previously for Porsche. I came here to seek help since I am not super knowledgeable about these engines since its a new platform to me

I think I have the connections between conversations lined up correctly:

What I'm saying is:

Post #15 Post #20 Post #39 Post #44 Post #50 . . . this has been mentioned a bunch of times as we are trying to troubleshoot a hesitation issue. Based on this, I have to suspect that you believe the natural roughness that you and others note is either a normal thing, or a problem. Since your mentionings appear to assert that this is normal, we really don't have a path forward for the perceived roughness of the idle of this engine nor large OHV engines in general. At the same time, since it has been mentioned so many times, I see it as possible that you would like to troubleshoot this as well and/or know of this as a symptom for our troubleshooting of this issue. Both of those directions are in conflict with one another.

I have more experience than many with small through large OHV gasoline engines from GM, Ford, Chrysler, and even some AMC ranging in size from 3.5L to 8.1L and with fuel injection and with carburetors. In general, they run pretty smoothly when in good condition, and are generally able to pass the wine glass test while warmed up. When they aren't warmed up, have mechanical issues, and/or have marginal parts (plugs, coils, wires, filters, injectors, etc.), the computer controlled units can sometimes exhibit a pattern of occasional bits of roughness while searching about for the right ratio to keep then engine running as commanded while keeping the catalytic converter at optimum temperature.

Another trend that I've noticed in this thread is:

Post #20 Post #44 Post #50 Post #51 BMW typically works very hard to isolate any drivetrain vibrations from the occupants. Porsche as well. A 2012 Chevy Express 3500 with LT trim doesn't really try to isolate the occupants from anything, and also adds to the harshness by being a giant tin can. At 113,000 miles, the engine is now broken in but also less than perfect. What little isolation that has been done is now twelve years and a bazillion heat and weather cycles old. Also, the typical BMW and Porsche engines are designed to rev high and operate with higher torque peaks and shorter strokes than most OHV V-8'*. That by itself could add some inherent vibration potential. Another trend that is pretty much true of all engines is that the faster they spin, the smoother they are. Most LSes idle at or just under 600RPM while most OHC engines that I've seen idle at 650-750RPM. That would smooth things out for the OHC engines as well. In short, you probably will notice a little more harshness from this Chevy Express 3500 lumberjack than from BMW and Porsche ballerinas.

All of this isn't intended as an attack, but rather to provide some context for what you are experiencing based on what I know of your past experience. I think overall it sounds like it is in good shape, but there'* something that we are all missing here.

I forget:

​​​​​​​Does it have new spark plug wires?

Has it ever had intake manifold gaskets replaced?

I am aware of bmw'* efforts to control harmonics and overall engine operation, but they do also use an inline 6 in a lot of vehicles which is the most inherently balanced (primary and secondary) engine known to man. That was kinda what I was saying earlier when I said my buddy see'* the LS and LT engines idle a little bit rougher.

New intake manifold gaskets (it already came with the green gasket update but i did them anyway)
New plugs and wires at 70 something thousand