The Camaro 6 has some serious potential for tuning, while the 370Z is almost completely tapped out tune wise for an engine. The Z motor is nearing the end of it's era, as they have to now turbo charge to get over that 420-430 HP bump after seriously modifying the engine. I know a lot of people who have tried, and blew the block because too much pressure and heat. The BMW motor has the same issue on the straight 6, only so much can be brought out before it becomes a time-bomb. Right about the same horsepower range as the Z also. Hell, they both have trouble running without being tuned :P
The car is gone, I will be back... when's the 6th gen ZL1?