Re: Opinions on side cocking upper.
Going with a side cocking receiver + bcg from fulton will run you about 200 more than using a slick side upper and reg bcg will.
Ask yourself how often you want to manipulate the action/use the forward assist. Probably never.
Put that 200 towards something that you'll actually use on the rifle aka better trigger/barrel etc...
PS - JSEsurplus has DPMS uppers + charging handles for 165 and TDSguns in Rocklin (about an hour and a half from you) has DPMS BCG's on sale for 150.