If you intend to track your car, dont get an auto. I've had both auto and manual zeds. For the majority of time, i definitely preferred having an auto.. Easy to drive, and importantly easy to drive fast on a country lane. However on a track, when you need to make sure you're in the right gear at the right time, whilst maintaining grip levels etc - this is almost impossible with the 350z auto.
That said - i would happily buy another auto zed.