Not too familiar with the small early ADS 200/300 but did own 8 ohm versions of the Braun L200/L300 in 1978, or so.
The ADS models (late 70's) looked exactly the same.
There were also 4 ohm versions of the Braun L200/L300 (the ones I saw had captive speakers cables, but I'm not certain if such is a given standard).
Per the link Hififan provided one post denotes the ADS "I" models as for car/auto use, so I'm guessing that they are 4 ohm designs.
My Brauns did not state "8 ohms" but just had "8" on the back labels.
I powered them with various PP tube amps and both sounded better on the 8 ohm taps.
I would also run (my car) the L200's off a 12V capable Advent 300 receiver/Nakamichi 250/350 (?) cassette deck when driving down to Mexico or up to San Francisco (didn't leave the setup in my hatchback car when I was home in LA/Hollywood due to possible theft/broken windows.
The L200/L300 were considerably better than Radio Shack "7" look-a-like, but care needed to taken with the woofers in all of them (watch the power and SPL levels).
DeKay