Yes the heavy vinyl tiles are ideal. And you can place them on the outside of the cabinet if you want. You will have to figure out a way to glue them on.
You can also upgrade the cap and resistor used in the woofer circuit.
I think the speaker terminals that you are referring to are these: http://gr-research.com/electracabletubeconnectors.aspx
Read through that material. It is very enlightening.