If this is a lower end would it be worth to sell and upgrade to Saiga or something higher end?
If the sights are straight, the mag doesn't wobble, and it shoots reliably and accurately, there is no reason to get rid of the WASR. A good WASR will shoot just as good as a Saiga; it just won't look quite as good while doing it.
But that shouldn't stop you from getting a Saiga as well. I love mine!