Oh, there is one more thing. Right now, in Aces High, the P-38L and the Me-109K are very evenly matched. The P-38 is running at 60" Hg. MAP, which puts out 1,600 horsepower, and the 109 is running at 1.8 ata, which is 1,850 horsepower. Now if we raise the P-38's rating to the officially cleared (though not in the Pilots Manual) 66", we get about 1,750 horsepower on the P-38. Now, imagine how much better the P-38 would perform than the Me-109 in the game, under those conditions - and it's still running a lower rating.
Of course, then the Me-109 could be raised to 1.98 ata, which does 2,000 hp. But then the P-38 could be similarly raised to 75", which also yields about 2,000 horsepower. Since the 1,600 hp. P-38 does well against the 1,850 hp. Messerschmitt in Aces High, and since Kweassa and I both independently calculated that the P-38 does better versus the Me-109 the higher the boosts go, then I think it's safe to say that a 2000 hp. P-38 would do very well against a 2,000 hp. Me-109. And 2000 horsepower isn't even the highest rating I've heard of a P-38L using in combat.