I wish I had a nickel for every time this question is asked.
1) Can you change the oil in your car?
2) Have you had wood or metal shop in high school?
3) Do you own a drill?
If you answered 'yes' to any of the above, you are qualified to convert your own Saiga.
It is about as difficult as opening a newfangled plastic blister pack.
YOU DO NOT WANT any stock that just bolts on. The balance will be way off and you'll tire of it quickly and start bad mouthing all of us who have balanced functional conversions.