Anyone tried the Sprinco double spring recoil reducers for Glock pistols? I'd be interested to know if they do anything to tame the recoil of a Glock 23.

From Glockmeister's Product and Service Advisory Page:

4. Please take our advice and do not purchase or use recoil buffer systems. The stock recoil spring performs perfectly - the gun does not maintain reliability if the recoil system is changed. Some of the most common problems that we see with these systems are a failure to feed or a failure to eject properly. In the most extreme cases, we have seen catastrophic failures related to recoil buffer systems.

I have a Sprinco recoil reducer in my Glock 35, that I used for IPSC shooting several years ago.  I have put almost 7,000 rounds through the gun using this recoil rod and noticed little or no change in recoil, and no changes in malfunction rate.

All my malfunctions were magazine or reload induced.

I haven't tried one in my G23, but I doubt you'd notice much of a difference in the recoil.