Tuning before delivery?

One thing is you won't be able to get a tune for it until you can provide them (the tuner) with your computer code that is printed on a sticker in the engine bay. If you're talking about just using the SCT to change values, I'm not sure about that, but I wouldn't do it.

If I'm not mistaken, the mid-muffler system is after the cats, so no tuning adjustments should be required at all. Just slap it on and go.

If it does remove the cats, all that will happen is you'll throw a code letting you know that the cats are malfuntioning. That can be remedied with a tune or some MIL eliminators.

Mine made 2 miles from the dealer before I changed the exhaust & I had no problems. But they are right on the tuner thing you have to have the computer code.