From a stop when dumping the clutch or aggressively accelerating, there's a loud solid clunking noise on the rear left side of the car. Think wheel hop, but it's some someone is hitting a hammer on the underbody.

Subframe bushing? Differential bushings?

 

strut mounts. When was the last time you replaced them?

 

could be strut mounts, diff bushings or subframe bushings, maybe even motor mounts.

idle the car and rev it from the engine bay to see if you have movement

or put the car on jack stands so and shake the wheels and check for any play

 

Differential bushings most likely, these are common to go bad in the SC and Supra.

 

Thanks all for input. Not sure what it is yet, no resources to tackle the issue right now. - When I find out for sure I'll post.