here's what you should.....
find shops that have experience with dyno'ing mustangs and working on them
go to the shop....look at their operations, are they a clean organize shop or a bunch of friends running a garage that truely dont know what running a business is like. second find out what kind of experience they have, do they work with SCT for tuning, what kind of support will they give you AFTER the car is tuned.
i only say this because i have had the worst experience possible with my procharger install. what should have took me a weekend to install took over 60hrs to complete. plus the dyno shop i went to has the worst customer service possible. the tuner basically tuned the car for MAX power, but not drivability. so now the car pulls hard, but barely idles, dies randomly, extremely rich, fan is on all the time, and has a very unpredictable power band. i took the car back to get assistance and will not get any. so now i'm forced to find another shop...which i have (MPT tuning) and am currently in the process of datalogging the car through them.
so if you are going to have a shop do the work for you all i can say is....really do your homework