You're running a TD07 and cams and you're complaining about lag? Try running an Evo 8MR with standard turbo, a remap and 22psi and see what you think then, it's a fantastic combo for the street, although obviously not as powerful up top.
I think this question was answered a long time ago, but if you want to do weekend track work and have a quicker point-to-point car, then the Evo is hard to beat.
The GT-R is a powerful car that rewards talent and is more satisfying to drive.
It depends on whether you want to be faster or have more fun, really.