VEPR - 922R Compliance

I have been modifying 20 rd M14 mags for my VEPR and I think I need to check into 922R compliance issues... It came with a pistol grip stock which I have skelatonized and installed. Not sure if it is a US made part. I like the look of the original thumb hole stock but it does not fit my hand very well and it is a long reach for my trigger finger so I will probably stay with the PG stock... Any suggestions on what I need to do to get into compliance?

Anyone threaded the barrel for a flash hider or brake? Not much to work with ahead of the sight but probably doable... Carolina Shooters has a light load trigger main spring for AK's (about $15). I installed one in my Saiga 12 and I like it on that gun. Not sure if it would work in the VEPR as it has a 2 stage trigger and the Saiga does not... Looks the same just looking into the receiver... Is this a 922R part?

Just looking for some things that will make me legal...
MrE

Your gas piston 1 is an easy 922r part FCG 2 3 4 is your m14 mag us made that would be 5 6 7 plenty of parts you only need 6 with a threaded barrel

Is the gas piston in the VEPR the same as other AK rifles? I would like to make that change for 922R compliance but do not know where to buy the correct gas piston... Same questions about the FCG.

Carolina Shooters has a low tension main trigger spring that replaces the twisted wire original spring (reduces trigger pull force). I installed this in my Saiga 12 and like it... Does this american made spring count towards 922R compliance in either of these guns?

My VEPR does not have a threaded barrel. Has anyone threaded their barrel and can it be done without removing the front sight? I would like to add a flash hider/muzzle brake to the gun.
MrE