Here are a few shots of a quick mod we do. In order for the COBB downpipes to mate up to the factory Subaru exhaust they have a neckdown where the downpipe and midpipe meet. Even when you upgrade to a larger cat-back exhaust, the neckdown is still a choking point for the exhaust. By removing the neckdown you remove the choking point, allowing you to reap the full benefits of your aftermarket exhaust setup. In addition to removing the neckdown, when we do this modification we replace the warp and leak prone 2-bolt style flanges with v-band flanges. The V-Bands allow the connection to be more easily serviced, and they hold up better in performance applications, as they are less prone to warping and exhaust leaks.