These have replaced my Alpine coaxials, and are quite the speaker. Since installing these, I have felt little need to figure out how to get another subwoofer into the car, as it now seems almost unnecessary. I’ve still got the amplifier channel for it, so if a good one comes along, I won’t turn it down; but I don’t need one anymore. When tuned and crossed over properly, these speakers rival anything I’ve heard from a coaxial driver, and most mid-level consumer grade component systems (I had Polk DXi components in the doors for a couple months, those now look like Wal-Mart speakers in comparison). The bass is incredibly rich without sounding muddy in any way, the mids are clear without the stress usually associated with too much midrange, in the way you get from iCrud earbuds, and the high frequencies seem soft but present, without the typical harshness associated with metal drivers. This being said, I drive them off of an old Eclipse 5-channel amplifier mounted in place of the factory McIntosh unit, and I personally wouldn’t recommend using them directly on a head unit. Their sensitivity is high enough that you could run it off the deck without a problem, but the extra clarity and head room gained from using an external amplifier will not be regretted.