You are probably better off to save a little more though as the replicas are a little dodgy
Then why don't you buy a brand-new one?
I AM DEAD SERIOUS. There is a German company that is building brand-new P-51 airframes, to original factory spec (with the one difference being that modern machinery can put it together much better then the originals.) They started out building brand-new Fw-190 airframes! And there's even a group out there building
brand-new Me-262s, including the engines, although they are not at the point where they're outright manufacturing new airframes for commercial sale.
I want to be perfectly clear-
brand-new P-51 and Fw-190 airframes are being built. Not a 3/4ths replica with a lawnmower engine; no, a real P-51 airframe. (You'll still never be able to afford one in your lifetime, but hey, it's cool!) One of the problems with old warbirds is that they've got 60+ years of strain and metal fatigue on their airframes; you have to fly them conservatively and they won't last forever. With these kits being built... these planes can take to the air in mint condition once again. And for "cheaper," too; the kit is $475,000 and the site claims you can put together a whole aircraft for around $750,000. (That translates to buying the Merlin engine, of which there are quite a few still floating around, in great condition.) Of course there are approximately eleventy billion small parts (landing gear light mounts and the like) which one would have to aqquire, but the point is that odds and ends of complete P-51s are much more plentiful then P-51 airframes themselves.
Apologies for the words words words, but every time I think about the rebirth of two of the most iconic fighter planes ever to fly, I get excited.