www.rbprecision.com/BIG +1 !
Robert and his Krista are great, hands down AR supporters and have great prices on there lowers.
Find out what you want...Lower, grip, stock, FCG, bla..., bla..., then call RB-Precision and tell them what you are looking for! They will usualy quote you a price right over the phone!
If you are going to a show that they will be at you can usualy do the transaction right over the phone and pick up the lower at the show!
Robert got me exactly what I wanted for my RRA Lower, and I picked it up the following week at Kane!
Good luck!