PPE headers arriving next week and I ordered the magnaflow cats too. Do the cats make the headers a lot more quiet? I want the car to be loud still, only reason I might install the cats is to reduce gas smell

 

I have Magnaflow high flow cats on mine, they make it very slightly quieter. Almost negligible difference. The smell is very different though, I couldn't stand going catless for more than a week because of the smell