Originally Posted by Slo86GT
Is it more idiotic to think that the Borla exhaust that Shelby is putting on the car provides 0 extra horsepower as well?
It's possible. Aftermarket exhausts have been shown to give minimal to no gains over the stock SVT exhaust. Plus without a tune, the ECU might not know how to properly utilize an upgraded exhaust. Or perhaps Borla/Shelby just haven't dyno'd and documented the before/after yet. IIRC the Borla kit is still a work in progress at this point, and hasn't been officially released.
Mine: 2006 Mazda3 s GT Hatch: 111k, Gray, Manual
Gone: 2002 SVT, #1654
Hers: 2010 Focus SES: 84k, Ebony, Auto, Moon and Tune