HHR now offers our primary cat delete pipes specifically for the 957 (2007-2010) GTS non-Turbo V8 model. The primary cat is replaced with straight through 3" downpipes. These GTS-specific downpipes are different from those used on the Turbo models.
These downpipes reduce backpressure, getting your Cayenne into the power band quickly. In addition, the downpipes increase horsepower from this bolt-on item without an ECU tune and even greater performance after an ECU tune.
HHR downpipes are handmade in metro Denver, Colorado. The tubing and flanges are made from 304 stainless steel. We use 3" 16 gauge mandrel bend tubing which mates up to the factory exhaust manifolds and secondary cats. The flanges are 3/8 inch 304 stainless steel, CAD-designed to match the Porsche flanges and are precision waterjet-cut in our own facility. We include 1 O2 sensor fitting per side on these downpipes, identical to the factory setup. We ship this product with O2 spacers to help reduce the occurrence of check-engine-light issues.
This is a more complex install, however, it can be a DIY project. The factory/dealer expects this to be a 7-hour installation, but plan for more time just in case. Installation is relatively easy but time-consuming due to the tight space and limited access for removing the factory downpipes. After the factory pipes are removed, installation of your new HHR pipes is easier because there will be more space.
Free shipping is offered on this product for the Continental US only. Please contact us for a shipping quote to other countries/locations.