You want to replace the cats first then get it tuned. Random Techs aren't that expensive and what many people run.
[2004 GTO PBM A4
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
2011 Corvette - Torch Red - A6-- Cam, Headers, Exhaust
2013 Ford Focus - Grey Metallic