Pistonheads is all about driving, fun, driver involvement and interaction with car. They talk a lot about it, actually they published video how you can properly heel and toe. Thats the reason why they prefer manual. It's not about speed or high hp, it's about fun, sunday morning hoons and so on.
Supra community doesn't talk about driving that much, if all. There is a ton of discussion how to mod our car and make it more powerful and so on, but there is not a lot of threads where we actually discus something about driving and/or improving our driver skills.
Personally i would choose everytime n/a manual over TT auto (same goes for example 911 too). I know that auto box in supra is good unit, but manual offers more of driver involvement and fun ect ect and blah blah.