don't add cats. You don't want to add cats. You have 6 as it is.ok so if I did decide to add on like cats, CAI, gears after tuner ..... canned = good , custom = no good...?
A tune is just their to bring all the mods you have to work together properly. Canned tunes are good, and custom tunes are good as well. It all depends on the tuner.