what's the difference between the two? i know cat-back gives performance and axle back gives next to nothing, what else?

 

They both give next to no gains, they're all basically sound mods. The stock pipes flow very well and will support major horsepower numbers. There is a small crimp in the factory pipes over the axle that some want to replace but any gains are negligible. In my case, I cut off the factory pipes when I installed a Pypes MM system so when I decided to change the exhaust I had to buy a cat back because I had no factory pipes. If I got to do it all over again I would have just bought the Borla Stinger axleback from the get go.