I think the OP needs to ask himself the question, what do I want from a driving experience standpoint in a Supra? The last thing you want is thinking that your missing something from the car every time you drive it.
For me I always knew that I wanted a TT6 and have never regretted it since. Every time I drive my car its an adventure and that does not mean I'm hooning around in it all the time.
Even going for a gentle Sunday drive, the car is so engaging.
I'd advise to go out in both an auto and manual car to get a feel of both and then make a decision based on that. Also put in to perspective what your long term and end goals are with the car. It's better to plan now and save money in the future.