Hello friends. It's time to replace my cats and I want to go with test pipes and I'm supercharged. Do I need to retune?

 

I would, The last guy I remember change out parts with the Kit blew up, granted he went to headers, but you are still increasing flow, You'll lose PSI also so I would for sure get a retune and I wouldn't do any WOT pulls till I get it.

 

Test pipes.... yes you will lose pressure but you'll be continuing replacing cats.