Seam sealer & Sound mat

[RPBurris]

Ok. I am getting close to finishing up welding in all of the floor patches and getting anxious. Just want to make sure that i go about this in the proper order. I am planning on first painting (just roll on black satin) on the whole floor to seal any bare metal, then seam seal, then sound mat. So I have a few questions: 1. Paint first right? 2. If I am doing a self adhesive sound mat do I still need seam sealer? 3. What is a good budget friendly sound mat you guys have used and like? I live close to the Alsip Eastwood store and they have some of their X-Mat on sale. Almost 35 sqft for $80. What are the thoughts here? Thanks in advance.