This is a bad idea.

Your talking about replacing 6 drivers on a perfectly good set of speakers because of a minor defect on one driver. After all you said you have to get your ear right to the woofer to hear the rattle. Also, keep in mind that any woofer will rattle or distort if driven to its limits. The paradigm drivers and crossover network were designed as a system. Your messing with alot of R&D when you start thinking "I can make it better then the Paradigm/Kilpsh/Polk/Boston/B&W/Dynaudio designers did." There is a much better chance that it will sound worse, not better. Also, if you start drilling holes and junk your going to kill your resale on speakers that hold their value very well.

If you want more bass, buy and EQ, turn up the bass knob, get new speakers, or add a sub.

The only time you want to start taking apart and putting together speakers is when you don't mind the prospect of destroying them altogether and when your doing it for fun. I've put together some pretty fun "Frankespeakers" over the years. But if these are relatively new good condition kilobuck speakers, I would be very hesitant to start redesigning them.