Baldeagle's spot on. Really, the P-40 is an excellent diver. You don't need much neg. pitch to keep up those kinds of speeds in that bird.
Listen, I know it's frustrating when it happens, but when a good stick gets a high bounce on you, don't go and post on the forums that they are cheating. Especially without a film to back it up. Not only does HTC frown on this, but you will ruin your respect with the rest of the AH community. And, to keep in perspective, if it wasn't for the other players, we would all still be playing boxed sims.