Most manufacturers will say DO NOT USE +P+ as their is no set ceiling on pressure. I have 4 different +P+ types of ammo and to be honest some +P have more severe recoil, but recoil doesn't always reflect pressure. I would go on the Sig forum and ask this question, also if the beretta M9 can handle Nato rounds I would not hesitate to fire them in an SP2022, this gun is built soundly. I have the SP2022 with the Ifalon finish and have shot numerous rounds both standard, +p and +p+ and the gun shows no problems. I believe a steady diet of +p and +P+ will increase wear, but as far as longevitiy, it all depends upon the design and strength of materials and recoil spring rating.
Some companies say +p is fine on some of their guns, I believe some of CZ's models reflect this. With todays litigating, ambulance chasing, dirt bag lawyers, companies play it safe.