Tim, this has been discussed in the past here... Some feel that the cone style filters may suffer somewhat in performance because they are not shielded or enclosed, and tend to take in some of the higher temperature air under the hood and behind the radiator, whereas the K&N's in the stock or aftermarket airbox should emit cooler air from the NAACA duct only. I personally have a cone style system (like the BTR set-up) and like the looks and performance (I've had both). I don't know if anyone has positively proven there is a performance loss or gain with either set-up, but perhaps others will comment.