K&N filter replacement over stock filter

[m3f_Jcolem3]

I have about 20,000 miles on my OEM air filter. Would it be worth getting a k&n filter to replace the factory one? Is there any performance gains from this?

[m3f_95Hellrotm3]

Yep, there sure are performance gains, but hey, why dont you just go for a CIS (coldair intake system) instead for more?

[m3f_ARCpolo_6b20514d39]

I have a ECIS intake system. it is basically a 8" K & N cone filter, an inlet tube and a heatshield. The setup is very nice and it does give you aound 8-10 hp gain. Plus a very cool intake noise. So I would look into an intake system unless you want to keep your car stock, then go with a K & N filter drop in and maybe debaffle your airbox for an extra few hp.

[m3f_Jcolem3]

How do I debaffle the airbox? Does this affect anything in regards to the computer reading airflow?

[m3f_Jcolem3]

Speaking of horsepower gains... Is there a site that has actual dyno print outs of the M3's stock and with different mods.