you aren't going to see a difference in performance with a 3 vs a 2.75 unless you are boosted most likely. 3 inch systems take up a lot of room underneath the car. If your lowered you will have a hard time getting it setup in the right position so it doesn't scrape the axle or body. My friend it dealing with that right now with his 3 inch magnaflows.
2014 Black 5.0 Track Pack with to many mods.