I think the P-51 was vulnerable to spin at lower speeds and more suited to boom-n-zoom fighting.
(but not quite the deathtrap as the P-39 Aircobra)
https://aviation.stackexchange.com/questions/40999/does-it-really-take-9000-feet-to-recover-from-a-spin-in-a-p-51-mustang
US Army Air Force spin tests found here resulted in an average of 3000-6000 ft alt loss.