Just to make sure that I'm not out to lunch (no comments), the imported parts in a stamped receiver Romy would be:
 (1) Barrels
 (2) Mounting blocks (trunions)
 (3) Bolts
 (4) Bolt carriers
 (5) Muzzle attachments
 (6) Buttstocks, wood or folding
 (7) Forearm handguards
 (8) Magazine body
 (9) Followers
 (10) Floorplates

The USA parts would be
 (1) Receiver, stamped
 (2) Trigger             (*)
 (3) Hammer           (*)
 (4) Disconnector   (*)
 (5) Pistol grip        (*)
 (6) Gas piston       (*)

(*) All supplied by buying the Tapco compliance kit.

That way I would be in compliance with 922 using either domestic and foreign mags.

Thanks,
Terry  (aka fuzzy_dba)

yes
but its cheaper and easyer to use a us brake instead of piston
if your rifles dosnt have a brake them you only need 5