If your cousin is the one selling it for only $100 he is either desperately in need of cash or the world's nicest cousin. I'm not sure if you are trying to tell me I'm wrong or I'm just not understanding you but the Longbow isn't made by AGD. The Tac One is made by AGD but the parts that make the Longbow a Longbow are made by Special Ops. The stock Tac One already has great accuracy because it runs on HPA (which is regulated already) and the Automag Xvalve adds a second level of regulation so the Tac One when broken in will shoot +/- 2fps every time the Longbow stuff looks awesome but contributes nothing to the accuracy of an already first class marker.
Tac One
Longbow crap Pay close attention to the marketing not that you need to since it comes across so thick that you can't miss it.