The higher the sensitivity, the less power (watts) is need to produce a given level of sound from the speaker. So 92dB is better than 80dB in that you need less power to produce a given sound level with the 92dB speaker, as compared to the 80dB.

Speaker power ratings are usually deceptive. It seems that the cheaper the speaker, the higher the power rating...lol. Is the rating 'peak' watts or 'RMS'? If it says 100W on the box, that could mean the speaker can handle 100W of peak power (likely) or 100W continuous power (highly unlikely). Don't pay much attention to this rating.

Resistance, actually impedance, is also important - rated in ohms. It represents resistance to the flow of current (amps). So, a higher rating represents a greater resistance to the flow of current, which means you'd want a lower resistance, where possible.

You won't hurt any of your speakers by using your existing head unit unless you drive the head unit amp to clipping by turning up the volume too high, causing distortion.

__________________
Chris
2007 E550 4Matic - 61,000 Km - Iridium Silver, black leather, Sport package, Premium 2 package
2007 GL450 4Matic - 62,000 Km - Obsidian Black Metallic, black leather, all options
1998 E430 - sold
1989 300E - 333,000 Km - sold
1977 280E - sold
1971 250 - retired

"And a frign hat. They gave me a hat at the annual benefits meeting. I said. how does this benefit me. I dont have anything from the company.. So they gave me a hat." - TheDon