just wanted to know if anyboby is using the magnaflow hi flo cats on ther L or screw and did they notice a difference after removing the other two thanks 72 mustang

 

I've got them on my 2000 5.4 flareside and I could tell that it freed up some horsepower and the sound was much deeper and louder, you cant go wrong with the free flow cats

 

I just put some high-flows on my Expy, along with a true dual Magnaflow setup with an x-pipe.

Pulls a lot harder now, but I had partially plugged cats that were full of carbon...

I gutted my pre-cats, so that it appears they are till there. Great for passing the CA visual inspection.