Yeah, I had Atlantic tweak my base tune too. There were a couple spots where my car was leaning out a little more than was comfortable. You have to remember that these are production cars with variance between each of them. The base map is a really good starting place and is generally safe but even just as insurance, an hour on the dyno with a wideband hooked up is very much worthwhile.

 

Just to provide some perspective on how much variation there is between different types of dynos, when I got my Ralliart tuned on a Dynapack 2000 a few years ago with only a couple minor mods it said that the car was putting out 261 peak hp. Now, a few years later with a lot more mods done to the car, the dyno-tune I just got on CBRD's Mustang Dyno says that my car is only putting out 247 peak hp(a DECREASE of 14 hp!). I'm sure if I had taken the car back to the place I got it tuned the first time with the Dynapack 2000, I would have put up peak hp numbers in the 280's or 290's.