I started with the stock airbox, went to a pod in a cold airbox with cold air feed, and then back to the standard air box with an Apexi panel filter.
When I changed back to the standard air box, I could notice the following:
- less top end pull
- much better lower end torque for day to day driving
- quieter
If you decide to get a pod, definitely get a heat shield and pipe some cold air to it. I'd recommend a dry/paper filter, not an oiled one like K&N. In a test the Apexi filter had the best filtration and flows just as well or better than the others. It is dry so you can just blow it out with an air compressor when it needs cleaning - ie no messy oil kits.