Not all ford T5's are created equal....

[Para]

I am going to start first with rounding up engine, trans & rear end before I buy the kit so I have a ton of questions
I assume a T5 out of a 2005 - 2010 mustang is the Trans to go with because of the lower 1st gear?

What did t5 transmissions come in?
Changes and Improvements to the T-5 Transmission
Year Range First Gear Third Gear
1983-1984 2.95 1.34
1985-1989 3.35 1.29
1990-2005 3.35 1.26
2005-2010 3.75 1.41

[j.miller]

1st gear is moot point. You will never spend much time in it no matter the ratio...da Bat

[cob427sc]

He's correct. First gear is just to crawl out of the garage and not hitting the wife's poorly parked car. Other than that you don't need it much except for burning up tires. Rear end gears are more importatnt.