Pony talk

as for stability and fuselage tank, the Mustangs we fly with have both their central tanks removed to accommodate a jump seat, but aerobatics are still possible without issues. The real problem was probably the fact that fuel would wash around, causing longitudinal instability.

@ Galway: pilots' comments like the one you posted are what have probably negatively influenced the thoughts and ideas of people who are not into aviation but are passionate about it.
The Spitfire is one of the most over-rated aeroplanes in history, not for its characteristics per se, but mainly for the propaganda fame that it gained.
As of today, I have never met a pilot who has flown both the Spit and Mustang and thinks the former is better (apart for turns that is): under a piloting point of view everything is so functional and well arranged (controls, systems, visibility), and performance wise the experience is breath taking.
The Spitfire might handle better in turns because it's a light machine with a beautiful wing, but the Mustang is superior in pretty much every other aspect.
The idea of "the best plane is the one that can turn tighter" is unfortunately a die hard myth..
The reality is that most of the aeroplanes that flew with the Spitfire were equal if not superior in terms of overall performance..

The P-51 delivered all that it was needed for, and then some. Its performance, range, punch, manoeuverability and versatility made it the most cost effective fighter of WW2, anyone who says the contrary is just plain wrong.