I seen that they are discontinuing the Bridgestone S-04 pole position tires. The two best tires that I have used on my Z through the years are the S-04's and the discontinued Goodyear Eagle F1 Gs-D3's (both 280 treadwear). They both maintained good consistent grip through the life of the tires and lasted about 20,000 miles. I ran a set of Michelin Pilot Sport PS2's (220 tread wear - when I owned my G35) which had good grip but they only lasted about 10,000 miles. My Yokohama Advan VS5 wheels came with Yokohama tires when I bought them from Stillen but I remember that after about 10,000 miles they started to get "greasy" even though they had plenty of tread life left.
I realize that it depends on what you use your Z for (track use or general driving) but just wanted to hear what others think.