You can't base comparisons of historical performance on present day warbirds. The restored Bf-109s, P-51s, B-17s, A6Ms, etc. lack the armor and armament carried by the operational aircraft and are almost never flown with a full internal fuel load, thus weighing up to several thousand pounds less than their wartime predecessors. More importantly, they are not powered by the same engines, even lacking the emergency boost systems that were all-important to vertical maneuver performance. Since they almost never fly above 10,000 feet, few of the later generation restored warbirds, such as the P-51, have an auxiliary stage supercharger, which gave the P-51 its speed. The B-29s that have been restored (two, I believe) all use a modified Wright R-3350 based on the engine model that powered the AD Skyraider in Korea and Vietnam - it produces up to 600 more horsepower at sea level than the version that powered the B-29 in WWII, but lacks the turbosupercharger. One wartime B-29 pilot who had the opportunity co-pilot a restored aircraft said something like "They sure didn't take off like this when we flew them!"
As a result of all these modifications, their c.g can vary somewhat from the operational versions, depending upon whether ballast has been added to compensate for the missing armor, armament, fuel, supercharger installations, etc. This could really affect the flight characteristics of the Bf-109G, whose approach and landing characteristics were described by some Luftwaffe test pilots as "malicious."
For game purposes, comparisons should only come from the original manufacturer and service flight tests (which are available if you have the time, means, and patience to go through archived material that is usually not available online), or through the USAAF TAIC flight test reports (many or which are available online, if you have the patience to search). TAIC tested most of the German, Italian, and Japanese aircraft that were flyable after capture, and some of the data was surprising.