Are you planning on a 70 or 80 series. I built the 70 series. Just a few parts more on 80. Also look around in the
http://forums.1911forum.com/ and ask questions
You have lots of options. For parts: MidwayUSA.com , Brownell's, Fusion Firearms, Wilson's Combat, Brazo's, Les Baer, Ed Brown, Bar-sto Barrels, Storm Lake barrels. Numrich gun parts is more the original parts.
For the frame guts I used Olympic Arms sear, disconnect, sear spring, hammer, Beaver tail safety and extended slide release because it save about 50%.
For the slide I went with Caspian Commander Slide in .38/9mm. With Novak sight cuts. Novak offers lots sights Caspsian is well know for its quality.
Drop in Bar-sto SS barrel, Someone told me that all Bar-sto barrels are National Match and I think that they are. Even with a drop in you will still need minor fitting.
For main spring housing I used an Smith & Alexander again I got it at 50% off.
Most parts these days are quality parts, it just depends on what you want to use. If you want low end parts Sarco Inc is a good source.
You can buy directly from Caspian, Bar-sto or you can get them at MidwayUSA.
When fitting your parts together just take your time. Tools you will need small files, plastic or rubber hammer, hard stone for polishing, small screw driver, steel wool or scotch bright for polishing.
For the magazine I went with Mec-Gar, it is less expensive than Wilson's and follower has a piece that bends back in the magazine preventing the follower form tilting foward.
When your buy your frame have the ejector and plunger tube installed, it is easier to have them do it.
Good luck
