What you need to do is find out exactly where these cars are, and ask on this site if there's a member living close by (with a good bit of knowledge of the z), who would be willing to view the car with you. Failing that, ask somebody you know that knows a bit about cars.
With such a low mileage car as that nismo, you really need to make sure the mileage is genuine and have a good look at the service book, it should have at least 5 service stamps, as its more than 5 years old. A yearly service is the minimum requirement!! Check for wear on the seats, gear lever and pedals. If excessive something isn't right. The steering wheel usually holds up well to any wear. Most importantly check the bodywork for any imperfections and signs of repairs from crash damage. With less than 12000 miles on that zed it should be near to showroom condition, but bear in mind that it is over 5 yrs old and will have the odd mark here and there.
If i had the money i'd snap his fingers off for that car