If you want to pay dealership prices for the tint, there's an advantage to having it already done when you pick up the car and folding the cost into any financing.
Flip side is you don't pick the installer, get to talk with them about what you want to achieve, see different tints, and choose what best meets you needs.
I'd suggest you pick up the phone and talk to the dealer about it ASAP, find out the costs and options. Then get onto Yelp or Kudzu or similar, look up well rated tint shops in your area, and get on the phone with them too.
In the end, much like your dinner, laundry detergent, and underwear, you do need to decide what's important to you vs. what's important to a bunch of strangers.