As the best starfighter pilot in the galaxy, does Poe enjoy the privilege of a technically more advanced X-Wing model or at least the freedom to modify it? Is it technically different from stock X-Wings of the period?
TFA Incredible Cross-Sections page 12 says:
"The T-70 X-wing is a favourite craft of Resistance pilots, including Poe Dameron, who flies a customised example codenamed Black One."
However, what constitutes "customized" is not clear - it could refer to its custom black color; or to special configuration of modular bays (which ALL T-70s have according to the book), OR real customization not available to other X-Wings.
Neither novelization nor film script mention specific details.
As the Rebel force's acknowledged "top pilot" Poe appears to have had some latitude to customise the ships at his disposal.
As well as explicitly confirming that Poe's "Black One" X-wing is a customised ship, the film's 'Incredible Cross-Sections' book states that the black paint is more than just an affectation, it's actually a
"Sensor-scattering ferrospehere paint"
The film's "Visual Dictionary" backs this up, stating that that the paint-job makes his X-wing especially hard to track and easily
overlooked by sensors.
Presumably this aids his dogfighting (the ship is hard to see on sensors and visually) as well as making it useful for the sort of infiltration mission he's on at the start of the film.