Now now
Whether the reports are accurate or not- I can't say. These seem legit, but I am the first to say: don't use one source in research
I have to admit though:
a P-51B-5-NA going at this level of performance:
Maximum speed at critical altitudes. (67" Hg. man. pressure & 3000 RPM)
Low Blower at 16,600 feet 430.0 MPH
High Blower at 29,400 feet 442.0 MPH
Is not something that I have seen in the sim allowing for airspeed correction, maybe I'm doing something wrong. On a 55* day, you'd need over 300 mph indicated @ 16000 feet to correct your airspeed to close to 430 mph
RoC also seems interesting to me for that aircraft:
Rate of climb at critical altitudes. (67" Hg. man. pressure & 3000 RPM)
Low Blower at 13,800 feet 3450 ft/min.
High Blower at 25,500 feet 2660 ft/min.
that is, I presume,
initial climb. It's nice to note that these tests were done as follows:
"High speed and climb performances have been completed on this airplane at a take-off weight of 9205 lbs. This loading corresponds to the average P-51B combat weight with full oil, 180 gallons of fuel and specified armament and ammunition."
I doubt very much that 3450 f/min was sustainable for anything like an extended period- that data is not on the report that I can see
Now naturally there are better P-51 jocks around than some people are willing to admit, and of course good tactical control and flying discipline were real-life aspects of combat that were used to great effect..I see no reason that the same should not apply to the sim
Now personally I make any P-51 wallow and stall 50% of the time at high alt. I'm not patient enough. But I do see, when I'm being ham-fisted, Luftwaffe aircraft flying rings around me as I fight to keep from a spin. Should I conclude that those German planes are too uber?

The rope-a-dope tactic is embarrassing but I certainly do not let that from preventing my own use of it to win ACM
And Bosh's point is excellent. You can't assume that respective climb rates in a dogfight are like a race to alt from co-E, and so must fall back to a black and white chart. if one plane climbs great but is low and slow, but another climbs OK but has tons of E, what is it that's going to make the low and slow plane out-climb the E-hog?