Go for K&N typhoon when it comes out next year
This should be good (I hope)
The Injen and AEM are the best for your money at the moment (with proven dyno on this forum).

AEM actually use the K&N airfilter at the end of their intake duct. K&N typhoon copy injen or AEM duct with a different filter.
One would hope the K&N typhoon will be good
It might worth the wait

 

I love the Civic Si action sound. rrrrrrrrrrBWHAAAAAAAAAAAA at 6000 rpms.

 

If you're in So Cal, Spugen may be a good choice.

 

hehe...the best vtec sound I have heard was AEM CAI+Mugen header+tababe cat back on my old Type R...it sounds SO aggresive