I agree with the quiet insert as the least expensive option. A fresh repack wouldn't hurt, either. Get yourself a nice rivet gun for a few bucks, and the correct size rivets. Take the back half of the pipe off and drill out both ends of the can. Pack the perforated inner core as tightly as you can with fresh packing, and wrap it near each end and in the middle with 3/4" masking tape. Then slide the can over the packing. Go with as much as you can possibly wrap and stuff into the can. Then install your end cap, quiet or otherwise. Like Hick says, the stocker won't pass even with fresh packing, but the combo of that and a quiet insert will make a big difference. A fresh repack on a stock system tends to take the sharp "rap" out of the exhaust note.