Stall Size
If you had stayed with a LOCKUP tranny then you could run 34-3600 Edge, Yank, Vigilante and had streetability and performance. With the A3 you will have to pick performance or streetability due to the lack of lockup.
When you say A3 you mean TH350 or TH400 right? They are both strong and have their place but have crappy first gears and no lockup meaning crappy for the street. Well there were lockup TH350s but they are NOT a performance tranny.
The stock tranny for the automatic cars was a 4L60E, it gets a lot of bad press but that is due to incompetent builders, the good shift kit for it costs around $100 so if you can find a rebuild 4L60E with a shift kit for $200 RUN away.
A 4L60E has a great first gear, it is a big jump to second gear BUT the lockup means you can use 2800+ stalls comfortable on a daily driver which goes a long ways towards making the 1-2 gearing difference a non-issue.

