I have a tendency to purchase old dirt bikes, and enjoy rejuvenating them from the engine all the way through to suspension. In the case of my 2004 CRF450R, I purchased Gold Valves to maximize the performance of the front forks. The Gold Valves enable a high degree of tune-ability, and are pretty straight forward to install, although you should spend extra time making sure you have the valve stacks built correctly, and that you follow the install directions closely.
After a complete fork rebuild, and inclusion of these Gold Valves, my fork feels nimble and responsive. I highly recommend this product, with a caution that you should follow the directions closely during build and install.