[jazig.k]

its worth doing.
at least youll know a little more about your car and how the air moves around it, where the turbulance is etc.
probably worth doing for the rear bar where the air will be exiting so you can make some kind of comparison for when the diffuser is on the car. id think the air exits quite roughly at the moment, so youd just wanna 'calm the wool down' with the diffuser on. would be a starting point for a home test.