As soon as the parts arrived from C&L, we rushed to Lamotta Performance to install it. Lamotta had the '11 on the dyno when we got there, ready for a baseline pulls. In stock trim, it made 371 rwhp and 363 lb-ft of torque. Lamotta then installed the cold-air kit (PN 10699-11-PI) and called Chris Johnson of SCT to tune the combination. Though the cold-air intake can be used in a non-tune application, the results are better when combined with a tune. Once Johnson made the changes in his tune (which we tested last month) to complement the cold-air kit, Lamotta's GT spun the rollers on the Dynojet to 397 rwhp and 380 lb-ft of torque.
The exhaust components were next. Lamotta and Lamotta Performance technician Matt Gagliardi teamed up for the install. Once all of the old components were removed, the two installed the new SW components. "This kit is really nice," remarked Lamotta. "And the new headers went in easier than the stock ones came out."

Though an off-road option...

Though an off-road option is offered by Stainless Works, we opted for the kit with catalytic converters (PN M11HDRCAT). This can be used with either the SW or stock after-cat system.

The Stainless Works after-cat...

The Stainless Works after-cat system is made of 3-inch, mandrel-bent 304 stainless steel.

The Stainless Works mufflers...

The Stainless Works mufflers are visibly smaller than the stock ones, and feature a 4-inch, double-wall conical tip. "Because it's double-walled, it's less likely to change colors like most other tips," said Anthony Grosser of Stainless Works.
After everything was installed and tightened, Lamotta checked for leaks (there weren't any) and went for a test drive. Lamotta then strapped the Grabber Blue coupe to the dyno, and Johnson worked his tuning magic once again. The results were impressive-419 rwhp and 384 lb-ft of torque-a 48hp and 21-lb-ft improvement over stock. Not bad for a couple of bolt-ons. Not to mention, it sounds much more aggressive at idle and throughout the entire rpm range.
So how does the '11 GT compare to the '03-'04 SVT Cobra when it comes to bolt-ons? Well, considering the Cobra is supercharged and the '11 is naturally aspirated, a 48-rwhp gain is noteworthy compared to the Terminator's 55-rwhp gain with similar bolt-ons.
The real value is in overall power output versus purchase price. You can buy an '11 GT today for the same amount (or less) than a new Cobra cost eight years ago. Install a cold-air intake, headers, exhaust, and a tune, and you can make 419 rwhp-one measly horse less than we made with that '03 Cobra with the air filter and after-cat in late 2002.
Apples to oranges, you say? Maybe. But there's no doubt that the new GT is arguably the best bang-for-your-buck Mustang ever-and it's just as responsive to bolt-ons.

The battery and battery tray...

The battery and battery tray must be removed to reach the header bolts.

Jake Lamotta and Matt Gagliardi...

Jake Lamotta and Matt Gagliardi of Lamotta Performance...

...removed...

...the stock mid-pipe...

...and after-cat.

They then began removing the...

They then began removing the stock exhaust manifolds.

Both the left and right engine...

Both the left and right engine mounts had to be removed to access some of the header bolts. The steering shaft must also be disconnected at the steering rack.

Gagliardi disconnected and...

Gagliardi disconnected and removed the starter.

After removing all of the...

After removing all of the bolts, the stock exhaust manifolds come out from underneath.