The only automatic that would handle a built 2JZ is a GM Turbo Hydramatic 400 - with a higher stall rpm convertor.. easily can take 500 lb/ft input torque..
you can mount a straight 6 in a RX but the car only becomes a drag car - whats the fun in that, If you are spending so much money then why not drop in a fully rebuilt 13BREW with single turbo and Haltech E6K, that would be the mutts nuts..
much much much crazier than a 2JZ or an RB26 and would not upset the suspension geometry also.