Originally Posted by Jonmartin
Well I agree to an extent makes no sense to try to get a custom tune on a stock car to me thats a waste but if you're going all out then things change and imo requires a custom tune. All of my previous experience has proven this since I had a catless system installed as well as pulley,airfilter etc. It made a huge difference for me and a few other people I know but thats just the way it goes.
If you are running a full catless exhaust system you should benefit from a proper custom tune.