The new FMs are interesting. For some reason I can't get an engine sound on the Zero, I have PropLoop.wav and it is set correctly in the .ini. But I get nothing. Another thing is they handle funny. I can't quite describe it, but they are not as responsive and as agile as they were in the old 06 FMs, this may be more accurate, I don't know. As far as things unique to the FMs, the mustang always wants to nose down in flight, even with the wing leveler it doesn't fly level, as for the zero it has some serious problems with taking off. It goes hard to the right and even full rudder wont fix it. The AI can't take off, they just run around in circles. Also the instruments in the pit have a purple outline to them for some reason. Oh, and the Mustang and Zero wont fight each other. I set up a fighter sweep in either in 1944 and I get a mission accomplished as soon as I start.
Anyways, that's all I have found so far. I hope that is helpful. This was all done in '08 WOE.