Well, maybe I spoke too soon
http://www.ebay.co.uk/itm/07-07-NISSAN- ... 591wt_1396
10K but with 54k on the clock and Twilight Grey
From what I've seen,Twilight Grey is definitely the most common colour for the 313 roadster. They did come in an assortment of colours, Black, Midnight Blue, Rosso Red, Pearl White, Universal Silver and Temper Orange but most of those are pretty rare or very rare (I've only ever seen one other 313 roadster in the flesh and that had been wrapped ).
Indeed the 313's engine is 80% different but the 0-62 time and the top speed is identical to the 2006 facelift models. The engines do have slightly different characteristics though. I don't have any working knowledge of the first facelift model but I think the only difference inside is the illuminated ignition switch and maybe the light in the door pocket. I paid some 17.9k for Caroline's 2008 313 roadster with 7k on the clock back in 2010, probably worth maybe 12-13k now but I think that apart from The limited edition GT4, it'll probably hold its price better than most of the Zed range.
Pete