I know that you are most likely not wishing for this, but the chances of it being accepted is very nil. It saw either VERY VERY limited combat or none at all. Some say it was deployed in Soviet Russia, but never used. Other people believe that it was used in Manchuria, even if it was used in Manchuria it would be very slim; could be false.
Here's a source that I have found, giving credit for ONE Japanese aircraft shot down.
http://www.americancombatplanes.com/p63_1.html All this production and delivery effort resulted in the destruction of only one Axis plane, a Japanese fighter shot down during the invasion of Manchuria.
You can find that in ¶ Eleven.
Anyhow their are many many topics created for this specific plane, almost fifteen. Before you post you should gather information on past posts, I'm not backseat modding or anything but I hope you absorb my constructive criticism through osmosis.
Now this is from
Wikipedia on the topic of the P-63.
I don't trust Wikipedia, but they're usually right about the models, if I were you I'd wish for the P-39K it has around 125 more HP than the normal models, I'm not sure of it's operational history though. Also I think since they tried to complete the P-40 line they definitely should complete the P-39s.
-FMJ