There is another current thread on a Peluso capsule possibly being used in a Neumann. While the posts at Klaus's forum are uniformly against that course of action, it hasn't been bounced over here. I don't know if it is because of the desire to protect the Neumann microphone, or if the Peluso capsule would be considered a "step up" from the Shure.
Getting back to the original question, my guess on how good the KSM-32 capsule is, if you are accustomed to very bright chinese K-67 clone capsules (without the compensation network which Neumann used originally to "eq" the capsule), then the KSM might be a step up. If you regularly use vintage and high end microphones, I suspect that there would not be a perceived need for this.
If you want to do a DIY electronics project, this capsule will probably be great. I've built and modified things that I've used proudly. Still, the first project that one usually undertakes often does not compete with commercial products. There can be a steep learning curve (soldering, component selection, layout and a variety of other things which go beyond the schematic) which causes the 4th or 5th attempt at a project to be much better than the first.
It seems that if you want to build something for the joy of the project, this is great. If you are looking to get a better microphone cheaply, this is not the most efficient path. Knowing what you want to accomplish is key in this (and many other) endeavor.
Galil