Half the fun of saiga rifles is making them the way you want.
The stock front end is fairly good for field use. A word of caution with scopes, be sure to leave a gap between the rear site and scope tube. You would be shocked at how much the scope moves in recoil.
I went with the Dinzag gas tube and lower retainer. And did the trigger conversion on mine. (I make the steel mags for the saiga and vepr .308s) We make a pretty solid 10 round that is about the same size as the factory 8 round. And a stamped steel 20 that will be out in about a month or so.