Yeah true, that's one reason my M4's going to be 95% G&P.
It shouldn't be bad, I think the M16 you had was an older one as you seemed to have more problems with it than I did with mine. Also, yours had white trades painted whereas mine were engraved.
It's G&P, it won't be a blank receiver! Why not build literally from scratch then, buy gearbox, motor, barrel, hop unit, everything separately?
I doubt they are as true as everyone says, just keep it clean after every game and use high quality BBs.