Finally found some time to compile the article about K&N filter options for the 2010/2009 VMax. The choices are great, the CM-9908 is my absolute favorite. True K&N - not a blue Made-In-China knockoff. 

If you have to keep the stock airbox (mainly for noise reasons) this filter should be for you. You can find them all over eBay and the Internet.

Power gains with all drop in filter options are limited, but in return you keep the stock airbox.

The Big Air outperforms all these filter options by more than 7 rwhps from 7k-10k rpm.

Check out the article here: http://www.starvmax.com/news/1-v-max-news/182-2010-vmax-dirty-filter-secrets