speedometer change
 

ok so the motor on my speedo has gone out, iv got a new cluster coming but its not a TT its an NA cluster, so i have to change the back piece that has the speed on it sence theres no cut out for the boost gauge on the NA. So il just use the origional back piece sence it has the cut out. But my question is there anything else i need to do to make sure i get the correct speed? Thankes in advance.