Recently swapped to 3.73's from 3.31 on my 14 GT M6. I flashed the stock tune back to the car, then selected my AED performance 93 tune and before I uploaded I changed the gear ratio to the new 3.73. Tune loaded fine etc but my speedo is showing 10mph faster than what I'm actually driving, tire size has remained the same what am I missing? Thought the gear selection change in my X4 should calibrate everything?