I am sure you are familiar with this thread, but if not:
2009 Nissan 370z invoice Price
I went with emailing first, you will probably get the internet sales guy that way and they many times are more willing to jump at an invoice price than the floor guys. 200 below is not out of the question, but you might get it in differenent ways. Free oil changes, free part (wheel locks - which if so please refer this
link). Your best bet for a tough choice is to do a pro/cons list, which does really work, think about what you gain/loose, finance, etc. If the pros are winning and a dealership has a price you are liking, then go for a first test drive and see if it is what you want.