DSA makes a milled aluminum top cover that does not need the "para cut". The cover has the scope rail, so it eliminates any possibility of original appearance. The para cut can be made in any receiver, but this cover eliminates the need to do any extra work.
DSA also makes a para bolt carrier. This thing isn't cheap, but it does get you another U.S. part.
I bought the top cover, para recoil spring set, and bolt carrier to go with my Sarco folding lower. These parts set me back about $235, but I had been unable to find a para carrier and I really like the DSA scope rail top cover on my Imbel. A para rear sight will run you another $55 to $60 from DSA. You can get various other sights that can be adapted to the para lower, as seen on the FALFiles.
The Sarco lower is stripped, but you can reuse the latch parts, hammer strut, and triggerguard from your parts kit. Be careful when you get around to refinishing it. There's a post on FALFiles showing the Sarco buttpad melted during a refinishing episode.
I bought 3 kits from Gunthings, and every one was underrated according to their descriptions. The kits are ugly on the outside, but cleaned up nicely. The bores were great and there wasn't excessive play once the bolt and carrier were installed in the receiver.
After looking at the Ammunitionstore.com ad, I would probably go with the Gunthings.com South African kit. It's a few dollars more, but it's not a jumble of mixed parts.
If you go with an FSE trigger group, U.S. piston, U.S. charging handle, DSA carrier, and U.S. floorplates, you'll have your 7 parts. This would allow you to use a cheaper Imbel imported receiver. Tapco carries the gas pistons, charging handles, and furniture (if you want to swap pistol grip and handguards).