ET's aren't slow, i used to have one, it was ace, never had mechanical issues with the engine
all the issues i had were ecu and wiring, as it is old skool crap, like real SHIT!!!!!!!
mine made 120kw at the wheels, lean as all crap with 9psi and rx7 cooler, its all power tho, torque wasn't great
saying that tho there are better options, ca18 is an easy swap and has more potential
if you were to do it, there would be some thought involved in engine mounts, sump and pick up, dizzy could be a problem and water inlet/outlets