These guys are way more qualified than I am to help you now with all the info out there. The only thing I wanted to mention is an observation based on this part of your explanation: "We are 90% surf . . ."

Check out the Exile SXT65 speakers before you change whatever you have on the tower. While I agree that getting what you have now working is probably the priority, if you do decide to upgrade you will kick yourself if you don't at least hear these before you decide what to do. Good luck!