A Cosmos purple '05/'06?!...
A Cosmos purple '05/'06?! Read on to find out how our ProCharged '04 GTO made gobs more power and acquired a better look and sound.
In our last installment, we tackled the installation of Stainless Works' gorgeous 1 3/4-inch primary long-tube headers, but what good are these great headers if we choke them up with the stock exhaust system? It just wouldn't be right to let the stock after-cat exhaust take the brunt of the increase in exhaust gases, so we had to find a way to replace the stock after-cat and give our supercharged GTO a much-needed dose of antihistamine.
It's no secret that most late-model GTO hobbyists seem to prefer the look of the '05/'06 rearend with a split exhaust on each side to that of the '04. What's not to love? A dual exhaust that actually looks like a dual exhaust and a more aggressive fascia design set the newer cars apart from the '04s.
So what do you do if you'd like the look of the '05/'06-style exhaust and rearend but still want the option of returning to the rare and possibly more collectible '04 style in the future? While this was an issue that plagued some owners for quite a while, Stainless Works stepped up to the plate and agreed to use our ProCharged project GTO to prototype and produce an exhaust that would allow a nearly bolt-on conversion from the '04 rear fascia to the '05/'06 style with an increase in horsepower and an aggressive tone.
To complete this upgrade, we needed the following GM parts: PN 92160320, the '05/'06 rear fascia that listed for $373.44; PN 92168891, the rear-fascia extension with the dual-exhaust openings that listed for $264.51; and finally, PN 92164723, the impact absorber for the '05/'06 dual-exhaust-style rear fascia that listed for $88.69 at press time. We, of course, also needed the Stainless Works '04-to-'05/'06 conversion exhaust, which is PN 04GTOTM05RB and has a retail price of $786.45.
Follow along as we prototype and install the first Stainless Works '04-to-'05/'06 conversion exhaust and take our Goat to the dyno to see how it breathes.
To begin the exhaust conversion, we had to convert the rear fascia to an '05/'06-style with dual-exhaust outlets. We removed the Phillips-head screws that retain the plastic panel at the rear of the trunk. These screws have small caps over them that must be pried up with a flat-blade screwdriver.