I was trying to find the details of the spring that I fitted, it didn't require a collar (was an exact replacement for the stock spring) and I thought it cost less than $100 (but maybe I am mistaken!! Will keep looking), I know the spring compressor cost $60 and struggled to compress the springs!! It definitely took about an hour to change the spring, but I recall I did not completely remove the shock from the bike, I unbolted the top and lower shock mounting bolts whilst supporting the rear of the bike with an engine hoist. I then unbolted the preload motor and wiring, this enabled me to drop the shock down out of the bottom of the bike and have the bottom of the shock about 5 inches below the swing arm. That was enough to fit the spring compressors (one on each side of the spring), compress the spring, remove the collar and slide the spring off. I then compressed the new spring, slid it over the shock and refitted the collar. removed the spring compressors and then raised the shock back into place and fitted the mounting bolts then reconnected the electrical plugs and put the preload motor and hydraulics back in place. It looked like it was going to be a lot of work to be able to get the preload motor to come out of the bike, which is why I did it this way rather then completely removing the shock from the bike!!
Just being lazy, but it did take about an hour!!
Gary