The P-47 flown was by Lindberg not Yaeger, it was a C model and the air force wanted to investigate its dive speed limitations compared to manufacturer quotes. He found Republic Air overstated its safe dive speed by more than 100mph and discovered some unairworthy features under aerobatic combat conditions, so the P-47D series was meant to fix those. The D has a higher safe dive speed than the C.
The Messer had a very clean and streamlined, lightweight airframe with a good divespeed, but suffered elevator and other control issues at very high speed. Despite the fact its airframe Mach limit is comparatively high (beaten only by things like the Spit and Mustang), it isn't much more than a thrown stone at that speed. These kind of figures are really just the bonus round on a gameshow, you've already lost control of the aircraft and corkscrewed 15km in a plummet and incredibly when most fighters would've desintegrated you're in one piece, but if you ever manage to land the thing it'll be joining the scrap heap.
Ratsel that's a very big can of worms you've opened but I don't think I'm really up to it today. In October 44 southern Germany and Bohemia trust me they were putting whatever was laying around the factory floor in anything except the K-4, G-10 and Erla lines (they made G-10 and K-4). Believe me some G-14 had 605A-1 crate motors in them and were barely more than restamped G-6s with an engine replacement and the new radio navigation set fitted, with an MW50 field kit slapped on and a guage bolted in. If the opportunity was there several G-6, particularly G-6/AS issued in Feb44 which had blown engines by April but were otherwise in perfect condition, were actually taken back to an assembly lot and had the update gear fitted, you can tell these by the heavier jig restamping, right over the old G-6 numbers.
And fuel was assigned by airfield, not aircraft models. By Jan45 the aircraft were assigned from the body of accessable remaining service fighters by what fuel was available where. If 5./JG301 had DB motors and 12./JG301 had DC motors then 5 staffeln gets sent to one field with B4 and 12 staffeln gets split and sent to another with C3.
The only evidence that 605DC or ASC motors ever used 1.98ata and C3 (ie. 2000hp trim) is the fact JG301 operated G-10 and G-14/AS but the airfield those staffeln were stationed was exclusively supplied with C3 fuel, there is no record of B4 deliveries or supply to them, only of C3. Since we know the G-10 exclusively used the DB-605D series engine from the 109K, these should have been the DC engine.
The Luftwaffe in 1945 simply sent the Antons to C3 fields, Messers and Doras to B4 fields, essentially letting chips lay where they fell because logistics and industry was so bad. The majority of G-10 and K-4 were at B4 fields with either not enough C3 delivered for their sortie rate or no C3 supplied. But even where a 605DB is using C3 fuel it doesn't have to be recalibrated, it can function at 1.8ata without using MW50, which improves throttle height at overboost.
The DC is just a DB engine with 1.98ata recalibration and spark tuning for C3. It's a field mod, takes seconds, the nomenclature is purely administrative and the stamping is for fuel identification.
Same with the ASM/AM deal, the M for MW50 was restamped onto A-1 and AS engines using the older chamber design but late series piston crowns. They're retuned for C3 fuel and 1.7ata overboost but are otherwise A-1 engines and A-1 engines fitted with a 603 blower. The D motor sought to find some kind of midpoint between the AM and ASM performance extremes (4500m and 6500m) greatly improve reliability and performance at lower engine settings on the basic A-1, oil cooling, airflow dynamics and bottom end were the big concerns. The ASB motor is a D motor bottom end used with the 603 blower, I've compared technical details between the ASB and DB and there are none other than the blower, which has slightly different performance curves at medium settings and is more fuel efficient.
So the G-14 in October 44 mostly got 605ASM and were low engine life hotrods with 1800bhp field performance and 1500hp overboost at 6000 metres. The only differences that weren't purely administrative between it and a G-6/AS in March 44 are MW50 kit, a guage and some new radios. If it was a factory conversion it got a new instrument panel, if it was done in the field the guage was just bolted to the cockpit interior. Some done in the field didn't get MW50, just the new radios but were still reclassified as G-14. Most G-6/AS didn't have MW50, all G-14/AS did. In March 1945 however the G-14/AS started getting the ASB motor when they came in for an engine replacement (the ASM and AM hole pistons at full throttle within dozens of flying hours), so a 1945 G-14 could be K-4 standard like the G-10.
The only difference between the 605A-1 and 605AS is they put a DB-603 blower on the AS and made some tuning changes, this experimentation was performed in early 1942 after they were playing around with GM-1 on the channel front for about a year. A higher altitude engine was a more long term fix for a high altitude interceptor, the Fw-190A had become preferred as a low-mid altitude one.
From the very beginning the 605A was designed to use about 1550hp at normal military but the piston crowns and combustion chambers just couldn't deliver and it had burn through problems even at 1475hp, the 1300hp restriction was placed until new piston crowns entered production, but it was always chasing 1550hp military (the 601A-1 actually achieves this in mid-43 at about 1500 metres but they wanted it on the bench).
By this time MW30 (meant for bombers) or MW50 was already planned for series production but the engine kits were still in the development and planning stages, BMW/Focke Wulf and Daimler/Messerschmitt had two different ideas and approaches on the subject, and Tank's höhenjäger team had already supplied the first interim Dora prototypes based off A-6 airframes and were finding the new Jumo 213A was underpowered in the heavy little airframe, so they didn't know what kind of overboost system they were going to try, whilst Tank actually asked for Daimler engines.
Oh christ there's so much to it. Look the moral of the story is that from 1944 to the end of the war the Me-109 had little in the way of standardised equipment, performance or specification by subtype and that was the whole idea of simplifying production. Instead of having categorised fitments you just had a custom order policy and everybody, JG26, JG301, JG54 all operated mixed formations by then, and then the Erla factory made their own fighter-only specification. G-6, G-8, G-14, G-10 and K-4 all leap into a big fog there, a G-14/AS in Feb45 can be higher spec than a G-10 in Dec44, the Erla G-10 is higher performing than a common K-4 but Erla also made a lightened and streamlined K-4 in 1945 that must've been the fastest Messer of the war (figures around 730km/h and higher are tossed around for Erla G-10).
You bring the impression Ratsel that it was organised all nicely like a comfy American airplane plant in Indiana wheat fields on a pleasant sunny afternoon. It wasn't. Models and fitments were all over the place. I've read authoritive accounts of simply grabbing engines from broken crates and putting them in mix and match G-6 airframes and sending it out the door in early 45, G-14 with crate 605A-1 bolted in because that was the engine available and artillery shells were popping all around the factory at the time.