My buddy who's a salesman at a Nissan dealer called me in to check out the first 370z they got in. Absolutely gorgeous car just a bit pricey. The one they had was $34k- then again the new STi's are close to 40k now. Just makes the SRT-6 an even sweeter deal.
Stock for stock I'm assuming they'd be very close. However it's normally aspirated thus doesn't respond to mods as well. There's no pulley/intake to miraculously get it into mid 12's.
Despite the change in exterior style I feel the interior made the biggest upgrade. It's definitely much higher-scale inside. More like a late model CTS with the leather wrapped dash.
EDIT: sorry for the silly orientation of the images- I just dragged/dropped them off the iPhone.