The typical guy that tracks his car upgrades his wheels/tires. With that out of the way the performance difference between the two really isn't that much. Same engine, same brakes. Different damper tuning and a minor weight difference.
~10,000mi in my GT350 and coming up on 1700 in my GT350R. This just is not true. I realize the spec sheet shows minor differences other than wheels but it’s more than the sum of its parts somehow.