Guide to gyro and accelerometer with Arduino including Kalman filtering

Awesome work

I am making a 3 axis rate table to measure how accurate the imu is.
I want to answer the following questions
1)For a given set of sensors, how can i get the best possible performance from my Kalman filter in estimating angles.
2)Now that the "optimal" Kalman filter code is identified, can i achieve better performance by choosing better gyros and accelerometers.