An interesting tuning option that was introduced with the new Pike was the "bottomless token". Its basically a plastic spacer that reduces volume in the positive air spring. The tokens screw into each other (for multiple tokens) and into the air cap.
Rockshox have now released a "Bottomless Tokens/Air Cap Kit" for the 32mm forks. The kit includes 5 tokens and a new 32mm internally threaded air cap. It works with Reba, SID, Revelation, RS1, Bluto and Argyle Air forks. Part number is 11.4018.032.002. Expect to pay around $30 for the kit.