For your manual swap! Keep the '5' speed spacer for 5MTs or run it without for 6MT. 
 
Fits:
1993-2011 Impreza
2002-2014 Impreza WRX
2004-2020 Impreza STI
1998-2009 Legacy GT
1996-2013 Forester XT
 
Stiffer transmission mounts give you a more connected feel with your car. The KEIN transmission mount kit will reduce most drivetrain movement, which efficiently transmits more power to the ground. This means more accurate launches during drag racing and autocross type events where you do not want drivetrain slop. Another feature the KEIN Transmission mounts have is a proper interlock built into it. The stock part is held together with bonded rubber and a couple of small tabs, which means it is possible that the OEM part could fail and leave your transmission disconnect from your chassis.
 
Due to the stiffer bushing material, this may introduce additional NVH (Noise, Vibration, Harshness).