I have a Hungarian SA 85M. I love the blonde wood thats on it and I found a Bulgarian lightning cut stock and pistol grip that matches the handguards perfectly. Now I need the correct number of US parts to keep it legal.

Since I don't want to purchase a US stock set, what internals do I have to change to keep the ATF from burning down my house?

Would a US trigger group and US gas piston be enough to make it legal or would I have to get a US bolt and carrier also?

I want to change as little as possible.

Also the stock and grip have some kind of shiny finish on it. What kind of finish can I use on the handgaurds to match it? Its just a clear coat of somekind.  

You could add a US made muzzle device.

Hey CAMPY just how many US parts are required?

Is there something besides the mag floorplates and followers I could change? So when I use a chinese 75rd drum I'll still be legal.

Just make sure your stock doesn't say "Made in Bulgaria".  They'll never know the difference, so they'll never be able to enforce the bullshit law.