Jorge thank you for responding, appreciate you taking the time out.
I own a TT Supra. The stock ceramic turbos are definitely noticeable, even in the cockpit with the windows up. Audio recordings while in the vehicle cannot pick up the same as your ears can and I believe that's what's misled you.
Either way, given that people are expecting the quintessential turbo sound for these cars, I would have thought that been the goal.
You'll find that generally single turbos have more of a spool hissing sound, where as the standard sequential setup is more of a whine.
As the car is in the game currently, I'd say it's closer to a single than a stock layout. What you're probably thinking of, is the turkey gobble sound when you let off the throttle. This is less to do with turbo type and more to do with the recirculation system. Air being forced back into the turbos results in the sound you're expecting.