I will join with smellie and Claven2. Leave the SKS as issued. It's one of those rifles that just are best left alone, and I'm not a purist! I've modded all sorts of things. They're good rifle just as they are.

Stock up on 10 round chargers and practice loading. It's really fast once you have learned good technique. Removable SKS mags are truly a BAD idea!
Scoping it won't help accuracy, unless your eyesight is the problem.