The Dynamixel AX-18A Smart Serial Servo from Robotis is a step up from the AX-12A servo providing twice the speed and 15% more torque. The AX-18A has additional feedback information such as speed, temperature, position and load.
The InvenSense MPU-6050 sensor contains an accelerometer and a gyroscope in a single chip. It is very accurate, this sensor is used in self balancing robots, drones, smartphones, etc. The sensor uses the I2C-bus to interface with microcontroller.