Not sure if many of you guys have heard about the flow stacks or the idea behind it. These basically help improve the airflow. Usually you will see about 5whp gains NA and Turbo.
Today I dynoed my car without a flow stack and with the universal BPi Flow Stack and Sentra specific JWT one. I must say I'm overly impressed with the BPi one. Note that BPi Flow stack made 230whp with a filter on.
http://www.bpinitiatives.com/
Dyno Chart
Video: http://www.youtube.com/watch?v=p36Eys29IMU