There may be some performance upgrade parts that you just won't find here. If you can't try "feral" Errol at datrats.com.au. I've bought from feral and it was a very smooth transaction. I was very happy in the end. He even packaged up some parts I'd bought from another member here and sent it with the parts I bought from him.

For more run of the mill parts, I've tried rockauto.com, local parts dealers and local nissan dealers (or try courtesyparts.com - the nissan dealership located here in dallas known for the ability to get hard to find stuff).

With more specifics we can help a little more. What year/model do you have?