The fast spy

Maximum speed: 591 km/h (319 knots, 367 mph) at 4,500 m (14,765 ft)
Cruise speed: 510 km/h (276 knots, 317 mph) at 4,500 m (14,765 ft) (60% power)

vs.

Maximum speed: 437 mph (380 kn, 703 km/h) at 25,000 ft (7,600 m)
Cruise speed: 362 mph (315 kn, 580 km/h)


The most major significant difference was service ceiling...and if they had lived to get there thru improvements, the P51's would have still ate their lunch at nearly 42.000 feet. Simply thru location and dive down tactics from a superior position.

another example of a very novel Nazi effort that still had no impact. primarily because its design intent, while good, in the effect-attempt to/of out performing pre ww2 fighters...it did not adequately address, afaic, potential improvements of their potential oppositions design and production of counter fighter defense.

loss of facilities, qualified personnel and resources doomed it as war progressed.