Welcome to ZED land . Having been around on this site for a couple of years and on my second one, it is quite clear the non GT versions are harder to sell and a trusted dealer friend has verified this several times. That said, if you want to install your own ice, not bothered about the leather and don't want to have a ready bluetooth set-up then maybe the saving is worth it. Personally, I find the criuse option quite useful on motorways and more so now with the increasing numbers of 'specs'. The accelerate/decelerate buttons can be used quite effectively on motorways - I found they were more responsive with the 276bhp engine compared to the 296bhp engine I now have - don't know how they are with the 313 though?
As your budget is a bit tight for a new one, then a well cared for one-owner GT would, IMO be your best bet. Personally I would be bit wary about demos - lets face it you do get the likes who have no intention of buying just wanting a free thrash* and frankly some salesmen are just as bad and if Nissan say a 1200 mile running in period should be observed there must a reeason for that.
* I've done that in days gone by just to experience the the car concerned and believe me on those occasions my right foot got very heavy
Have a look on Pistonheads and also the for sale section on this site for what you might get for your money. It is clear some are getting concerned about the present monetary situation are are selling virtually new cars for give-away prices so keep your eyes open for a bargain. Good luck.