just as a reminder. the headphone specs really do not let you know any thing about the sound quality of the headphones. not even frequencies response chart, but it give a small general idea about what the sound will be like.
53mm drivers
driver size probably does matter. not saying that bigger = better but the size can influences the sound. too big of a driver could mean less bass control for example. normal headphone use plastic diaphragm that move to produce sound. more expansive one use more expansive materials like that weird sony qualia one. there are special electrostatic headphone that dont use diaphragm but non-moving parts, or half and half.
Copper clad aluminum wire (CCAW) voice coils
Neodymium magnets
these two are inside/behind the diaphragm, typical in all headphones, but i dont know the science behind them. but i think the voice cord supposed to connect to the music signal. so if its cut off or burned out then no music.
5-40,000Hz frequency response
when manufacturer put extremely low and high number like this its mostly false claims or they reach those frequencies with major roll off or if its true it really doesnt matter that much, unless you're mastering music or something. the average human ears generally hear sound from 30hz-18khz (not even 20hz-20khz most of the time).
101dB/mW output S.P.L.
40 ohms impedance
the other guys answer know more than i do about this. generally low ohm and high spl mean the headphone is easier to power. a headphone with 600ohms for example, and only 90db/mw spl will require a powerful amp to drive to make it loud. i heard that there arent many heaphones with very low impedance and low sensitivity at the sametime.
2,000mW max. input power
how much power the headphone can withstand before you blow its driver/burn out voice cord.