Well, I was going to have a look at it, as I was pretty local to the seller, however the guy completely misread (or shall I say, read only the first sentence) my message at the end of the auction and sold it to somebody else.
:evil:
Turns out that someone over on the itr-dc5 was offered it and snapped it up. He has just received it, it looks as though it is in fact a N1, but with a different tailpiece welded on (the welds do not look as good a quality as the other welds).
Though I suspect the tailpipe is going to be very near (or touching) the bumper cutout. Also I doubt the bung that was suplied with it, will fit... so I might be well off that I didn't end up buying it... only time will tell.