Here are the best wheel locks you can buy period. They have a lug nut with a complex keyed top like other locking lug nuts, but also on top of that, there is a metal cap that can only be released with a special magnetic key. These are 12mm x1.25 so they are made to work with Nissan's. I absolutely LOVE these, but now I have a 1.5 pitch on my lugs because I switched to ARP, so I must get a new set of these to work with my new pitch. This will not be a problem for any other Z owner though.
Anyways, these are brand new, and only one was installed once. They are perfect! Brand new they were around $135 shipped plus a couple week wait. I will let them go for $120 shipped, and you'll get them in three days.