Why not ask the guy who's selling it? Cabinet impedance isn't hard to find out. Just put a meter across the input. It won't read the exact nominal impedance value, but it will be below that value, and fairly close to it. Might say 6.8 ohms, for instance, and you'd conclude that it's an 8 ohm cabinet.
There's no way anyone here can tell you if the Eminence drivers are original.
Tonewise, it depends a lot on the drivers, but it is a horn, and horns have certain characteristics.
Loud.
Band limited. This is a big horn, so you wouldn't lose much of anything on the low end as a result. Might lose some highs. This might be advantageous if you play with a lot of distortion.
Limited polar response (sometimes called dispersion). The sound will tend to project out into the room. It might be difficult to tell from on stage what the sound is like out in the audience, unless you kneel or crouch down in front of the cabinet. Actually, that's not a bad idea for everyone to try. Might be surprised. Anyway, limited polar response makes it a poor choice if you'll be playing rooms where the audience is likely to be very far off axis. Good for stadium gigs, bad for small clubs.
Those are my thought on it. YMMV
