Hawkeye hit the nail on the head with the comment that +P will wear the gun faster. My experience has been that +P is a bad idea in general, it beats up your pistol (including steel) and it beats up the shooter.
If you decide to shoot +P ammo I suggest that you install the next higher rated spring, before you start shooting. Also, limit the ammo to just enough to prove it will feed in your pistol reliably, and after that only shoot what you have been carrying in your magazine to prove it would have worked if needed.
Thanks for the replies. I called Kimber on this and was told that while they do not recommend +P, as it will accelerate wear and offers very little advantage, it will work. But if you are going to shoot +P it would be best to replace the 22 lb spring with a 24lb. Thanks again.
I've got a 4" CDP Pro and my 200gr +Ps buck a little less than 230gr hardball.
I just find a +P that shoots like my regular stuff and only use it in a lethal incounter.
BTW, Kimber sent me 24lb springs and it takes me 400 rounds to break in a new one. (so that I can fire single handed with no problems) Then they say replace them after 800 rnds! I think not, or I'll have a gun that is ready only 50% of the time. 1500 rnds sounds good to me. I only have a little bit of the "U" indintation on the frame after all this time.