Well, I say go for the nismo if you can live with cloth interior, here's why:
1. stereo can always be upgraded to better than OEM and you can even get nav in an aftermarket head unit.
2. The aero on the Nismo is functional, and since it's from the factory, it's going to fit better than most aftermarket stuff out there, plus you know it's been tested and proved to work at improving downforce.
3. the wheels are nice.
4. a bit more power
5. limited production (not really that limited but they do include a numbered plaque).
6. Has improved suspension already.
7. It's a Nismo and that's just ******* cool.
8. conclusion: get the Nismo.