You may want to try a quality high speed servo on the tail. If there is any vibration in the heli the piezo gyro is going to work the tail servo very hard. Most std servos are not made for this and burn out in a short time. You have to make a decision. A cheap servo for U$20 every 15 flights or a quality servo like the Futaba 9253 for U$80 that lasts a lot longer. If you are really tight with $ try a HS525 for U$30, it's a little better. But in the end I'd still go with the Futaba 401 gyro and 9253 servo combo for U$185. It only takes one crash when the tail rotor dies to cost more than the new gyro.

Fritz