I bought my genuine OEM(part #999W2-JT000) wheel locks on eBay from this seller for $25.95 shipped - they are brand new, as described, and come with full Nissan documentation including McGard registration card. These are usually over $40 shipped at a Nissan dealer online site... Btw, they also fit the 370Z, even though it's not listed.
NISSAN INFINITI WHEEL LOCKS BRAND NEW G37 G25 FX35 M35 EX35 MAXIMA | eBay