There was one guy on here who put a "Satchell Link" into his coupe (attaching bars from the axle housing to the chassis of the car like this /|\ (bottom of font is rear of car) - the two bars end up either side of the tailshaft tunnel - apparently their location can be optimised to prevent squat to help with I assume the location of the rear roll centre.

Maybe this could help when using JTS leaves, and possibly a rear sway bar.