Whoa, I didn't know the invoice was below 30K, but their prices are a little high. The yellow is a $500 option.
You should not pay more than $500 over invoice, but invoice on a base Z with automatic is like $30,300 on a manual it is like $29,700. Do you want a manual or an auto? If you feel like making the drive to Whitemarsh (just north of Bmore) then here are a couple options for you in different colors. If you don't want to make the drive then print out these pages and get your dealer to match the price. Most will do that.
Silver manual for 30K
2009 Nissan 370Z in White Marsh, MD- 5810235 at carmax.com
silver auto base with sport for 33K
2009 Nissan 370Z in White Marsh, MD- 5810235 at carmax.com
blue base with auto for $30,500
2009 Nissan 370Z in White Marsh, MD- 5982718 at carmax.com