casperorr

Hello,
I have a new 2007 Mustang GT with an automatic transmission with overdrive, and running 3:31 gears. Sofar I have two mod's: C&L cold air intake, and Tuner from Brenspeed. I am very happy with my purchase so far. I want to change to either 4:10's or 4:11's. Has anyone running an automatic done this? If so, how do you like it?
My biggest concerns in changing gears is creating problems.
1. Will changing hurt my automatic transmission?
2. Will this effect or hurt my traction control?
3. How is driving on the interstate?, also with overdrive?
4. Gas Milage is not my biggest concern.
5. Will changing my gears hurt my longevity in my drivetrain, (transmission, etc.)?

I have been considering this modification since I purchased my car. I would appreciate any experience and information that anyone can share with me. I want to get all the information I can on this modification so that I feel confident that I will not be headed for a mechanical HEADACHE.
I have had some tell me that it would be better not to mess with changing gears for Ford has setup our mustangs with their opinion of best combination of modifications. I would like to hear ALL OPINIONS.

Thank you,
Casper