Welcome aboard Tom.
The car I owned before my 350 was a Type R 30th Anniversary Edition so I know how much fun they can be. Definitely would recommend the 350Z though over the S2000 but maybe I'm biased now.
Buyers guide etc here; http://www.350z-uk.com/topic/22880-guide-for-new-memberspotential-buyers/
http://www.350z-uk.com/topic/77426-buyers-guide/