A few threads to get you started on:
FOr those ready to buy a 370/other new Nissan or Infiniti Vehicle
How I have scored invoice pricing with 3.99% APR on my 370Z?
From buying my own, I would not buy in unless I got invoice (which is what I got). The buyer has the upper hand currently and should be getting the price, within reason, he/she wants. I think the sport package is well worth the price for the upgrades, even as a daily driver. My Z currently is my DD, manual, and love everyday going to my car to go to work, school, or where ever I please. I enjoy driving again, where with my last car I hated it and always tried to get others to drive.