So you consider an optic a modification?
Given that it's a budget rifle, slap a Vortex Sparc on it and call it a day. Save yourself $800.
The OP considers it a modification as evidenced by his original post. He mentioned a trigger job and a red dot specifically along with a general "other." The general consensus is if he's going to modify the rifle, do it in a way that can be undone so the mods can be moved to an upgraded rifle. I can't remember anyone suggesting anything like changing the barrel or bolt carrier group.