As above really, tried searching but only came up with one TWM thread 
  
Was thinking about putting a short shift on the Z as i had one on my 36 and it was great along with a properly weighted gearknob, i know the Z's throw is quite short anyway but if you can get it shorter still and still get the same feel then that would be even better 
  
Ive seen advertised on various sites 
  
B&M, apparently not very good fitment and quality 
Nismo, havent heard a bad thing as expected 
TWM, seems pretty good aswell 
AMS, havent heard anything on these 
Japspeed, obviously wouldnt touch this with a barge pole 
  
They seem quite a rare thing to have on a Z, wondered if anyone had one on here or could tell me the best one to have?