Hello. The only +P+ ammunition I'll use is either Winchester 127-gr. or Federal's hotter version of their 115-gr. JHP. I couldn't tell you how much more pressure is produced than the SAAMI-approved limits for +P, but having seen quite a lot of both fired through various 9mm service pistols over the years, I don't think that it is waaaaay over the top..., but again I have no hard-and-fast facts.
+P+ ammunition from a quality manufacture is more likely to cause more wear-and-tear than standard pressure or +P, I would think, but I think it would take quite a bit of shooting it for this increase to become noticeable. At least it has so far in other pistols I've been shooting it through.
A very good +P load in my opinion is Speer's 124-gr. Gold Dot JHP and for folks preferring a standard pressure load, they offer the same weight Gold Dot as well. There are certainly others, but unofficial "anecdotal" reports I've been sent indicate that these do the trick with proper placement. The velocity differences between +P and +P+ varies and can be well under 100 ft/sec or, as in the case of the Federal 115-gr, considerably over that!
Best.