@ $99 they would be worth a try. a decent stock and LPK would cost that much.
i"m still not crazy about the carbon-fiber lowers. ever see a carbon fiber rotor come "unglued"? they like to fail at the worst possible times--LOL!
if there brittle-- i would worry about where the buffer tube attaches to the lower--that area is where poorly cast or improperly cured carbon lowers break off most of the time.
i have been running a cav-arms polymer lower for the past couple years. it is a soft but rigid type of ABS/nylon. so far it has held up well enough.
buy a couple of um and bury them i the back yard!
this is a vulcan CF i am thinking--broke right where the rear pin goes through the lower.
maybe they come up with a fix after all these years???
what is a 'plumcrazy" lower made from anyways?