I'm looking at getting a high flow cat for my car. I already have a fujitsubo exhaust and a comtech intake. Last year i got a VAFC and brought it in to get the car tuned and made some good power by leaning it out. So my question is should i get my car retuned after installing the high flow cat or is it going to make much of a difference in the A/F ratio. I not planning on adding any more mods... im just looking to get a little more sound from the exhaust...

 

high flow cat= more air flow. Requires more fuel. would help to retune.