Hi Rob, looking at the pics, the linkages change the travel by moving teh shock mounting point - the one on the left will give 190mm of travel and the 203mm. Whichever link is used, the shock will remain the same.
Looking at the picture posted by Josh, it is going to run a much larger shock that 190mm, especially if it is an 04(ish) era bike. By this point the likes of the Big Hit was running a 200+mm shock with a longish shock.
2015 Stanton Ti Switchback
2006 Specialized Demo 8
2013 Specialized Allez Sport
1999 Santa Cruz Chameleon
1994 Cannnondale Beast of the East (rebuild still in progress)