someone previously already reported the vibration at idling issue due to low rpm which is controlled by the ecu. unless tek has a way to reprogram the ecu, its pointless going back to them and better off going to a ws to do the reprogramming.
had the same issue on my other jap car and the rpm will drop 600+ on idle at traffic light causing the car to be a vibrator. lived with it for 30000+km and finally traded it off.
a few of my friends drive the mazda 6 2.0 and 2.5 and i can feel the vibration as well but havent heard them complaining yet though. they probably felt its a default feature or not too bothered by it.