No problem! Here are my thoughts on your questions:
1.) I agree the shape is better on the jm kit, but the diameter of the pipes is very large. Fluid velocity will drop proportionally as Cross sectional area increases, and the croossection increases at 3.14 × radius squared (Cross section increases much faster than diameter) so the exhaust gas hits the brakes when it enters the larger diameter area.
2.) Fluids do flow from higher pressure to lower pressure areas, but since it has mass it also has momentum when it's moving. And gases are also compressible, so they can resonate (think of a ported subwoofer enclosure). So even if there is less pressure in the 90 degree turn of the tee, that gas's momentum from bank 1 is pushing directly into bank 2, increasing that bank's pressure. Eventually the pressure in bank 2 will build up to a peak as the gas pulse loses its momentum. Depending when the exhaust valves in bank 2 open relative to the pressure peak, you could get the exact opposite of scavenging. Plus, now the pressure peak from the gas's momentum will push it back in the direction it came from (the resonant portion). But now it's aimed back into an opposite bank again (it's original bank). So the gases are just fighting them selves the whole way to the turbo. Could the resonant peak create a scavenging effect? Maybe at some certain rpm, but without testing or sophisticated modeling good luck predicting where. But I doubt you'll get any benefit from that manifold configuration. There's a reason why good headers all flow downstream and not up runners for other cylinders/bank of cylinders.
3.) Again the gas has momentum, so it will want to blow right past an abrupt 90 degree turn. With these manifold, the large diameter (and slower velocity) would actually reduce tendency for the gases momentum to carry it right past the 90. But you want to keep your velocity up before the turbo. Attached is a screenshot of Turbosmart's recommendations for WG orientation.
4.) Yes, that positiong is not ideal for preventing boost creep. And yes, that heat will be problematic, see that Turbosmart screenshot about keeping the actuator away from direct heat sources.
The runners on the Speedtech top mount are longer than the bottom mount, but still not that long. Plus they're not grossly over-sized. Take a look at 4n manifolds or any equal length runner, the long runners on a speedtech top mount are still shorter. Speedtech would be awesome if you could get it to fit.
I wouldn't worry about torque with the Hydras. They use vacuum wastegates, so you can easily limit boost at low rpm in your tune. Plus larger turbines and turbine housings will need more flow (rpm) to build boost anyway.
Holy smokes! this might be the most beneficial reply on a forum I think I have ever gotten, seriously, thank you so much. Really really great info here. It sounds worthwhile to try and get the Speedtech kit to fit (I think the bottom mount has a better shot of fitting the E60 than the top mount). Unfortunately it looks like options are quite slim for the E60 chassis, unless I get a positive response from Speedtech, so if that's the case I either have to pick the lesser of the 2 evils, or spend quite a bit more than I originally planned to spend assembling my own kit, which really isn't ideal for me, but neither is burning up a valve, or boost creeping into a block window.
1.) So with both kits we are going to run into a massive velocity decrease going from a relatively small cross-sectional area to something that looks nearly 1.5X the port tube, so spool on both kits are going to suffer drastically, as the exhaust gasses slow down to, essentially, fill the area of the larger diameter tube, meaning it's going to take much more gas flow/RPM to spin the turbine. (If I'm understanding that correctly?)
2-3.) Gotcha, so the BF Kit could be increasing exhaust port pressure as the gasses basically collide, instead of flowing to the area of least resistance they are going to continue movie in the direction of the elbow, which as you said, is the opposite bank, instead of flowing upward to the turbo. (I appreciate you explaining that, because it makes much more sense now that I think about it, I think I was thinking more of if pressure builds at the base of the T, it would essentially build to a point where the gasses would have only one way to flow -Upward-.)
4.) I think regardless of the direction I go, I'm fairly sure I have been talked out of the JF Kit, not only due to the WG placement in the system, but also what looks to have virtually no way to control boost on Bank 1, which really doesn't inspire confidence.
I was talking more in relation of Cyl6 length VS Cyl1 length, it looks like cylinder 4-6 are nearly twice as long as it's Cylinder 1-3 counterparts. But even still I prefer the manifold design of the bottom mount kit, and being more serviceable and moving heat away from the valve cover would be a nice benefit for consistent pulls.
It is my preference at this time to go with a single kit over twins, I think the Hydras look awesome, it looks like they work really really well too, but I'm more partial to the big single, at least for now. Spool time looks to be around the 4K mark with a lot of the single kits, which is around where my current 19T's spool.