Fly your opponents aircraft first... lucky we can do this.. and then fly the P51.
The P51 is fairly un-matched at high speed, at high altitude, where it mattered in WW2.
But down here on earth, in your computer chair, we like to do things differently... like dogfight with the P51.... Well if you know how to handle it, you're ok, but it's not really a DF machine, but a slash and burn for most users.
This is similar to the FW's, but the FW's pack a bigger cannon punch (50cals are porked you know

) so are more effective.
Try it out in all conditions, it's good experience.