Those are bose 151 environmental speakers rated at 6 ohms so fine for in car use. They are about £200/£250 a pair new ! And they don't need a different bose amp or equalizer. They are designed for outdoor use and boats so very rugged. They have 3 drivers from memory and are replaceable so even if ones blown, worth repairing!
so anyway, i got the old "hi-fi" out the loft, you know the type record player twin tape deck and radio all in one..... just to test the speakers, they sound absolutely freaking awesome so god knows how they'd sound with a good system driving them.
BrandBose Model151 SE MPN151SE, 34104 UPC017817343169, 2724260630668 Key Features Speaker TypeMain / Stereo Speakers MountingIn-Ceiling/In-Wall Construction3-Way Outdoor/IndoorOutdoor Technical Details Peak Power Handling50 watt Nominal Power50 watt Frequency Response40 Hz - 80 kHz Impedance8 ohm Sensitivity88 dB ConnectivityWired Design Exterior ColorBlack, White Dimensions Width12.5 in. Depth15.24 cm Height11.43 cm Woofer Size6.35 cm Tweeter Size6.35 cm.
most car audio stuff has zero impedance, so will run 8 ohm speakers no problem.....but as car audio head units and amps are ususally rated to 'see' a 4 ohm load, the 8 ohm speakers will only be seeing half their potential....in effect they will be under powered....which means they won't be driven....in short, they will be very quiet compared to a 4 ohm speaker at the same setting or just wire them in parallel....(you won't be running in stereo, but you will have full volume)