Made a big difference for me on my '03. I had previously installed a Progressive spring, just recently had the shock installed, along with servicing the actuator. Much better ride on straights, curves, slow speed, single or two up, just better all around, for me anyway. I did it at 52,000 miles.
The short answer is yes. I would also recommend the progressive springs for the forks. Some folks here say there is nothing except Traxxion. I have not ridden a Trax equipped bike so can not judge but believe me, Progressive is better than stock. ESPECIALLY old worn out stock. I also ride 2 up and pull a camper quite often.
As an additional note, 2 of my riding buddies have ridden my bike since the conversion and one already has new shock and springs and the other is just waiting for me to return north to help him with the mod.