Get the part # from the stealership. Sometimes they hesitate, make sure you get the FULL PART NUMBER. Something like #####-#####
Here are a couple of parts suppliers
http://www.infinitipartsusa.com/ Here is a dealership in AZ, which has good prices, for example I needed a corner light which my local dealership wanted $180 for, Pinnacle shipped it to me for $105
http://www.pinnacleinfiniti.com/