If you are willing to spend the bucks for premium rear shocks, you have to do something with the front besides adding a spacer. Buy two Progressive Suspension "Drop-In" Fork Spring Kits part number 10-2005 or 10-2201, 10-2203, 04, 05, 06, 10-2208, or 10-2210. Don't be concerned about what the kit fits because you don't care. Buy as cheaply as possible and even mix and match as you will discard the make up springs and everything else in the kits except for the 7" long springs (They are the same in all of the kit part numbers I listed.) Install 2 springs on top of each other with the large ends mated to each other at the middle in each fork. Cut 1/2" off the stock spring spacer to get back to stock height. Assemble and refill with 20 weight or heavier oil to the OEM height. (Sort of a ***** to put together because of the spring rates but possible using Triumph spring installation tools or equivalents.)
This is what I use in my bike and it works great. You will have almost double the spring rate (2.23/2 = 1.115 Kg/mm instead of .65 Kg/mm stock) which gets rid of the "dive to the bump damper" the R3 has when using the brakes or entering a corner. I was concerned that it would be too stiff but that is not the case if you use heavy enough oil. If you use light oil the front is underdampened and then reacts too fast. Although I do feel more of the super slab tar strips, the ride quality is not nearly as affected as you might think.
While this option costs about twice what normal Progressive replacement fork springs cost, none are available for the R3 inverted forks. So this is the only option I have found thus far short of having custom springs wound.
See http://www.progressivesuspension.com/pdfs/7100-105.pdf for a list of Progressive Suspension springs, shocks and their respective specifications.
