I talked to my local gunshop owner last night about buying an RRA lower for a new build. It came up in conversation that the parts you buy for a build may not be of the same quality as used in the complete rifles. The statement was "why else would it be cheaper to buy parts?" I understand that you lose the lifetime warranty when you build but you save almost $100. Is the money savings worth it and is there any validity to his point or is he just giving me a sales pitch?"

Find a new gunshop! The guy your talking too, doesn't know what he is talking about and who knows how far this lack of knowledge will go.

The parts sold individually are the exact same parts that they build the complete rifle out of, which is true of most (if not all) vendors. If what he said was true, then if you bought a complete rifle and the a spring broke, you'd have to call the vendor and they would have to replace it with the spring from the 'good' pile.

The reason you save by building yourself is because you don't pay the 11% (or somewhere around there) Federal Exice Tax on completed firearms.

You do lose the warrantly on the complete rifle, but not on the parts. Although this is also depended upon the manufacturer. Some will service a home built as if it were built in their factory, as long as all the parts are from them and it was properly assembled and not modified.

I agree with NEILFJ.  You also have to figure that you are saving on some labor costs.  You are putting it together instead of some guy at their factory.  

He does have one point though, to save some more money you could get some other company's internal parts or other.  That could compromise quality.  However, if you are buying all RRA parts, and you assemble it properly, then there should be no difference in quality.