I have a post-ban Polytech AK-47 with a Choate/Dragunov synthetic stock.  I want to switch it out for a pistol grip and put on a muzzle-break.  I know this is beating a dead horse, but I have read through the "Sticky" at the top on the '5 parts you need to keep your AK legal'.  I need your help and advice.  I don't know exactly which parts I should switch out for U.S. parts.  I also need help on where to get them.  I would like to put on a  muzzle-break as well, so I will need at least 6 U.S. parts.  This is my general plan so far:

1)  I want to buy a K-Var Four piece (polymer) Black US Stock Set  'Authentic Warsaw Pact standard butt stock length for all stamped receivers'.  Will this fit the Polytech?  I couldn't find a set that was specifically for Chinese rifles on their site.  Where else should I be looking for US stock sets that would fit a Chinese rifle?  This would give me at least 3 parts.

2)  I don't want to deal with followers/floor-plate changes.  I have too many mags to change them all and have no desire to worry about whether I'm putting an 'illegal' mag into the rifle.  I may change my mind later if it seems easier to do this.  So that would leave changing out the Fire Control Group and piston.  A couple of questions:  How difficult is it to switch out the FCG?  Is it something most people do themselves?  Does anyone have a link (here or otherwise) that shows how to do it?  Where can I buy a U.S. made FCG?  

3)  If I switched out the stock set and FCG, that would give me the 6 parts I need.  But I still want to know about the piston in case I don't switch out all 3 parts of the FCG.  Will the Tapco piston fit the Polytech?  Are there other sources for U.S. made pistons?  How difficult is it to unscrew the piston from the bolt carrier?

Thank you in advance for any help.  Answers to any of these questions will be helpful and links are also appreciated.

Handguards count as one part to the ATF, so the stock set is 3 US parts, and the fire control group hammer/trigger/sear is another 3 US parts.
Other than opinions varying on shepard's hooks, fcg swaps are easy. Many are happy with the adjustable Red Star Arms' fcg and retaining plate that replaces the shepard's hook. Plenty are happy with more money leftover and a Gordon Tech fcg.
I'm sure you'll have more posts on the stock fit come morning.

This is a stamped gun right? If so any stamped receiver stock set will fit, although most will require some fitting.  It's nothing you can't handle with even very basic tools.  

Just buy a complete US made FCG.  Most would recommend the RSA unit, but the FSE and Gordon tech units are also pretty good for less money.

Do those two and have your 6 parts without messing around with replacing the piston.  Replacing the piston would be more troube then the other two combined.  

That's what I think you should do.

I've got the k-var set on my maadi. I can't think of a reason why the set for the stamped receiver wouldn't fit your polytech. As for the FCG, I went with the Red Star FCG. All I had to do was a tiny bit of filing on the receiver where the trigger comes through to get it to pivot right. I put a US made brake on and called it good. I've got the US made piston still in the wrapper in the drawer of my tool box. I haven't swapped it out as it's theaded into the bolt carrier and pinned and just haven't had the time to do it.