02' GT 4.10's with Auto

[Triad`Stang]

I have the 02' GT with auto trans.. I was out cruising last night trying to get some seat time learning the car and to my shock on the stock street tires I cant do a Burnout without power breaking the car. ... seriously ! The car runs decent and best time so far I have run is a 9.3 1/8 mile. translates to 14.4 - 14.5 1/4 mile.
So the obvious upgrade I'm thinking is Gear swap to 4.10's... I know this has been asked 100 times, but

Times I can expect with just a gear swap over stock will be how much? Plse no estimates as many as you have done the gear swap lets see some real numbers.

Will the 4.10's pull harder no matter if its a 25 roll punch or is there an area the stocks are faster?