Exhaust question: Does a catback exhaust actually add any horsepower? I am debating which one to do.....any suggestions?

 

Not really, as our stock exhaust flows pretty well actually. The biggest gains will be from LTs, high flow cats or cat deletes. Cat deletes will give you about 20-30 whp without a tune, my high flows gave exactly 12 whp without the tune, and together with the AED dyno tune, my cat back and high flow cats added 33 whp and 50ish ft/lb.

 

If you do cat deletes, do you have an issue with annual inspections?

 

depends on where you get the annual inspections done...

 

Second GT and in my experience there's no hp improvement. My 2013 GT was dyno'd and nada!