I am looking at the bassanni x pipe with the cats.

I just installed a c&l intake and predetor c&l tune.

Would I need to retune the car if I installed the bassanni x pipe?

 

I didnt have to.

 

are you going with the hi flow cats? or off road?
If so yes it will go lean.
I had it on the dyno it went from 13.0 to 13.7

 

note the hi flow cats would be fine if you did not have a tune installed for the stock af is like 12.1 the hi flow cats pull it to around 13.0 and you will see more power.
put the c@l tune is set at 13.1 so it will go lean. On mine 4-7 on the c@l tune is like 5 on the rich side and i dont remember 2-4 maybe 3.5 rich does not change much on the low side.