I actually already have a set of Titan 550's from an E-MAXX, but those aren't the best of motors. The guy that recommended those only did because he didn't know what he was talking about
You didn't need a reverse direction motor, as you have two
seperate outbards and are not gearing the motors together, and any set of two of the same motors can be used in a dual setup, not just the Titan's.