most ATTESA controllers will allow you to set the maximum torque split, not the minimum torque split, which is what you want to do, effectively forcing a 50/50 torque split 100% of the time.
The ATTESA controller works off simple signals, so find the one that indicates traction loss at the rear wheels, then feed the ATTESA controller that signal constantly, and you'll have permanent AWD.
I can't imagine it being too healthy on the car's drivetrain though, as an Evo is designed to be a permanent AWD, wheras the GTR is a switchable RWD to AWD system. System developed using millions of dollars, vs $100 ATTESA controller :pinch: