I built mine from a Doublestar frame (centerfiresystems.com) $99O One thing when you swap the mainspring from one housing to another or just asseble one "if you get a totaly new assembly" I strongly suggest putting the housing in a vice to compress the spring into place and wear a pair of safety glasses.
If that little plug gets away from you and into an eye well kiss that eye Bye bye and get use to being nicknamed Cylops or Patch . That is one strong little spring and the cap is somewhat pointed .
Centerfire also has ARMSCOR 1911 parts (Armscor makes the parts for many 1911 badges) Got a slide and match bbl with Wilson Combat sites at a funshow (er, gunshow) for $80.00 and all the innards from friends free!
Your talking bout mebbe a $200 gun that shoots betteren any of my nines
ONE thing I recommend strongly is read as much as you can, get the Army manual on 1911 maintenance and whatever else you can get, even surplusrifles.com has an excellent how-to manual.
And before you start, get a cafeteria tray and put a rubber mat in it for your small parts and disassembly/reassembly area