The only problem I have with my car's DBW throttle is the immense lag during throttle closure. When I want to shift, I have to lift off the gas, pause until the car begins to engine brake, then put the clutch in. Otherwise, the revs take forever to drop, and sometimes they will go up when I put the clutch in. I have never had this problem with any cable throttle cars, or even my friend's DBW cars. It's all the calibration, and much like a lot of other aspects of this car, Mazda did a really shitty job.