True, great looking tips, better sound, and less weight are all enough to justify the cost of axle backs. I never dyno'd my car stock, and I don't believe axle backs increase power. However, with just the GT500 axle backs, k&n drop in air filter (in the factory air box), and a canned SCT 91 octane strategy tune (that came with the tuner), my car put down 409 rwhp on a stingy Mustang Dyno.

 

Great info Jarrod! I have couple of friends interested in the GT500 axle back and I hope they dyn they cars before and after installation.

Brian, this is a great rwhp number for these mods especially on a Mustang dyno!

 

I agree. My '11 5.0L GT made 16 more rwhp than my supercharged '07 GT on the same exact dyno (different day, though). The new 5.0L's are incredible from the factory and full of so much easy power potential.