Why is the Z slower than comparable cars?

Wicked Daddy

So my first post here (other than the intro) is sure to spark a debate but I feel it's a legit question.
I have been doing a lot of research on the Nismo Z, as I'm 90% sure it will be my next car. But I can't understand why it's 0-60 performance is slower than other cars that have less power and/or lower HP to weight ratios.

The various magazines like the handling and that is a good thing. But most will complain that it's under-powered while also complimenting the VQ as one of the best V6's ever built (I agree). Years ago the Z was described as a beast. Now it doesn't even make the list of top sports cars. What happened?

Personally, I love the looks of the Nismo and I can always increase the performance. But I also wonder what happened to the once, almost legendary reputation of this car. I still want one.