actually I think I read that it would be better for your transmission to have it tuned? But none the less having the ATX tuned will be a great improvement.
For what it costs for a tune I would do some more mods (intake, exhaust, etc) and then get a complete engine tune that includes the ATX (shift points, trans pressure, etc), make it worth your while.
If your serious about getting the tune talk to Tom or FSwerks.
2012 Fusion SE 3.0L V6
'86 XR4Ti ; 2.3L Turbo, 15psi
1988 F150 Custom
'07 ST ; formally bewst'd - R.I.P
D23 Crew: #07