first of all century didn't actually make any of the parts used on the century ar-15.
they just used off the shelf parts like everybody else- nothing at all wrong with it. i have seen one or two of them --they seemed to work OK--
sure you can put a DPMS,DSA, double star, MEGA, bushmaster, AA , or whatever lower on it if you want.
if it was me i would just use the rifle as is and buy more ammo.
if it ain't broke why try fixing it? just to make some mall-ninjas happy?
just shoot the hell out of it!--LOL!