We recently designed a performance intake system for the 2003-2006 Nissan 350Z. This included an airbox and filter that attaches to the end of the stock mass airflow (MAF) housing. Our results were positive in that we achieved a significant improvement in intake sound, and we increased power output by 10 whp and 13 wtq without any additional tuning.
This project is not so much performance oriented but is intended to add reliability and additional aesthetic appeal to the intake system on the Z.
To start this project, we rolled our test vehicle into our development facility and started inspecting the stock piece. Check out our test subject.

350Z intake hose test vehicle