Hi John.
Lets see...
1) The LFE is not the only thing that can damage speakers, but as long as you dont crank the volume to stadium-filling levels, you should be fine.
With a dedicated sub, you want to tell your receiver that all your speakers are SMALL so it will route all the sounds below ~100 hz to the sub.
2) Well... Bass Management is not the issue. A center improves the sound simply because it's right on top of the TV and gives positional clues.
But some people dont bother with a center at all. Just tell your receiver you dont have a center and it will create a 'phantom' center with the L/R speakers. Make sure the L/R speakers are toed-in to focus 1-2 feet in front of your listening position (the classic music arrangement).
3) For ordinary CD, the digital connection (optical) is prefered. Yes, the sound DOES usually flow through the DSP/DAC chips in the receiver to do bass management, level adjustment, time delays, etc.
4) Filters .. usually power-conditioners are more useful than filters. This link on
Voltage Regulators might shed some light.
If you want, "borrow" the $100 filter from the store and see if it has any effect on your system. Sometimes it does, sometime it does not. It depends upon how 'dirty' your AC service is at the time you listen/watch.
