Beginning after the secondary catalyst, the AWE Track Edition picks up right before the rear axle and provides a full single 3” route from this point, then splits to dual 3” tip outlets. The Track Edition has absolutely zero filter -- making its sole purpose to increase the volume out of the B48 engine while remaining completely 50-state emissions compliant (and saving weight and dollars along the way). A simple cut (at the factory cut point) is all it takes, and the Track Edition goes into place via four bolt-on locations. AWE includes a factory clamp for the cut point that allows drivers to easily swap back to their stock rear section if ever needed. Here’s some helpful guidance if you’re deciding between kits: Due to the structural differences between the 330i and 430i, we are recommending the following per application: for the 330i, with all factory emissions equipment in place, the Track Edition is recommended for those wanting an elevated exhaust experience from within the cabin. If you plan to upgrade anything further upstream on a 330i, consider the Touring Edition - if you go Touring Edition on your 330i without any upstream modifications, it will resemble the stock sound in the cabin. On the 430i, interior acoustics (since it’s a coupe) differ when compared to its sedan sibling -- aka it’s louder inside. For you 430i drivers, we are recommending the Touring Edition, as the sound is much more pronounced in the cabin on the 430i. The Track Edition on the 430i is a bit rowdy. TLDR: 330i go Track Edition, 430i go Touring Edition!