225 shifter mech on gearbox. With or without counter weight

Hi,

just finished the Quaife install on a 2004 box I had spare to go into my sons 2006. On final assembly he noticed that the selector unit on top of the box had the counter weight on the 2006 but was missing from the 2004. both boxes were ND0 -000 and both were from 225s.

Who has had experience with both and what is considered the better option for track day fun.