Don't forget you have to wash and re-oil the K&N filters periodically. I usually clean and re-oil it every year. You have to buy a K&N recharger kit that contains the cleaner solution and oil spray. When you oil it yourself it's very easy to put too much on where it will drip.

Don't expect any noticable change in HP on the 996. I swapped the BMC filter (same as K&N) with a new stock filter back to back and couldn't really notice any performance difference.

 

theres no real performance gain but what prolly 1 or 2 hp but the main difference is the air flow and how much more efficient it cleans the air. and the cone will void a warenty(sp?) due to the fact that you remove the air box. supposedly you run the risk of water getting in blah blah blah too much dirt stupid excuses like that. any dealer will find any excuse not to hounor warenty work.