save up for a stick conversion...
stick + mods - money for conversion > auto+mods
you wont really get anywhere with an auto. but if thats fun for you then go for it.
Don;t listen to that. Thats an amateur remark.
You ever wonder why TA's and Z28's come in autos? All about traction. Manuals can have a hard time with traction if they are puching a lot of power. A torque convertor would be a great mod for races fromt the line. The header (without the converotr) would be good for races from a roll. If you turbo the car or put some Nitrous on it, that would also be useful. There are many different routes to take in modding a car. It all depends on your setup and what you want. Catch my drift? You can do whatever you want, don't let a few internet remarks get you down.
Also, the shift pattern of an automatic is really limiting the performance!
In those cars you mentioned, power and torque are in abundance, so the shift pattern doesn't really matter in a 1/4 mile race.
In a celica however, the automatic pattern really isn't geared towards racing, it's geared towards fuel economy. In an automatic celica, GT or GTS, you will not beat much anything in the 1/4, unless it is also an auto.
Besides, automatics have horrible 0-60 times...gotta love those torque converters.