I'm on my 2nd (first was stolen). Great little guns. Accurate, easy to strip, small enough for pocket carry, and relatively cheap. By all means, get the Wolf springs. While you are at it, get the extra power recoil spring. The factory springs were made for a little weaker milspec round and the extra power spring (1 step up is sufficient) helps to tame the recoil a tad and keeps the slide from slapping the backstop so hard. Replacing both springs takes only a few minutes.
For the mainspring, you might have to experiment. The 18lb spring worked perfectly on my first gun. However, the 2nd gun was still to stiff in DA so I dropped down to the next weaker size (don't remember if it is 16lb or 17lb). Single-action trigger pull is great even with the stock spring.
There is a forum dedicated to P-64's . I actually belong to it but haven't been active for a while. I don't have the new URL handy because they changed servers and domain names since I was on.