I dont really see the point of converting a ex to a dx...but, hey...your car
as far as a dx ecu..it'll work with a 5 speed tranny..ecu's have nothing to do with the tranny...and besides, dx's are 5 speeds.
as far as converting your car to a dx...that's gonna be a bit of wiring to actually lessen your performance. there's nothing wrong with using a complete dx engine w/ the ex manifold and dizzy...that's your easiest route, really..