So I came across an article on the GT-R blog after googling the Mine's High Flow Throttle Bodies and ECU tune for reviews. The article talks about how Mine's goes the extra step for the throttle by porting it and retuning it. However, they also mention how Nissan took the time to fully coat the inside of the throttle body for the GT-R Spec V for better airflow characteristics.
A little digging turned up the news that that GT-R and the 370Z share the exact same throttle bodies (part numbers the same too) as expected.
163 Throttle Chamber :: Fuel & Engine Control :: Genuine Nissan Parts :: GTR Parts (R35) 2009-2010 :: Nissan Parts, NISMO and Nissan Accessories - Courtesyparts.com
163 Throttle Chamber :: Fuel & Engine Control :: Genuine Nissan Parts :: 370Z Parts (Z34) 2009-2010 :: Nissan Parts, NISMO and Nissan Accessories - Courtesyparts.com
I'm thinking that if there was a way to get ahold of some Spec-V throttle bodies, probably very difficult and too expensive but might be possible, they may be a bolt on upgrade for better throttle response.
Pics of the differences are at the link below.
GTR-World: Mine’s High Flow Throttle Body Report | Nissan GT-R News - GTRBlog.com