Interesting thread. Re the vents, I could get these wrapped, (Red) as that would be tough enough to protect from waring out. I have a few chaps i use so simple enough to do, just getting them out without damaging will be the tricky part, or even painted and lacquered?? Also surely the L/H drive vents are like for like as its the actual dash mould thats different, hence likely that the vents could be purchased and retro fitted? Seat belts, as mentioned earlier are an easy upgrade. Re the seat stitching, i know several class upholsterers that can undertake this. along with re trimming the steering wheel in Alcantara with the 12 o clock ring. So net net should be easy enough to add the "colour" to the interior.
I have specced a carbon black edition and this definitely comes with a flat bottom steering wheel