MCA Blue for sure. Contact MCA, tell them you after a comfortable street setup for your R34, they should send you a correctly set up set of suspension.
As mentioned, cheaper alternative is KYB replacement dampers.
Yeah looks like the seat was scratched.
My Subaru wagon's seats are in pretty good shape, it's a 200,000+ km ex-country car (so depends on how well it was maintained).
Have a good look at the plastics, around the handbrake, etc.
I sold mine for $600, very light rashing, centre caps, bald tyres. This was pre-"BNR32 boom" era though.
I'd say $400 considering one has a crack and no centre caps.