The GT4 is the 300BHP version. It has the 06 engine in the 05 exterior.
If the car was registered prior to 23 march 2006 (which the majority of GT4's are) then it has the added bonus of being in Band F car tax (£205), and not band G (£400 in 2008, £300 in 2007).
Sorry to see that this one wasnt up to scratch. If it helps just about ALL stone chips on 350Z's regardless of colour go down to the white primer, I have a few on my yellow, and also some harsh ones on the bumper will go down to the plastic. Bottom line is the paint just plain sucks on the 350Z, and the shape of the front end doesnt help matters when it comes to avoiding stone chips.
Any leather issues can usually be cleared up with some good TLC with leather clean and leather feed. Unless its already cracked, then its probably too late.
The coroding of the top of the gear lever is common too, although they could have cleaned the previous owners dead skin out of it
Mine was not in tip top condition either, the laquer was all but gone - a dremel and some autosol sorted it out though.
For that mileage and in the condition you describe, Id expect a couple of grand off that price at least, even at a main dealer.