Well, I just couldn't leave it alone. I installed a custom intake bought from eBay just as the N/A Legacy guys do. I had put one on my wife's Legacy and gave her good power with the sound to match. On the H6, the sound isn't as dominating as the 2.5's. But, man, does it sound good! I noticed a little bit better power, but the ecu still has to figure out what it wants to do with it. Like I said, the 2.5 liters benefited well from it and I'm hoping the H6 will, also. As of now I am still utilizing the oem air filter. I'm sure a K&N filter may yield better results and increase the sound a bit. If anyone is interested I can do a write-up for this very easy install.