+1 on what dillinger said. I agree completlyI mostly agree with Hillbilly - Kimber and H & K both rate their production pistols as +P compatible right from the factory. They DO NOT require you to upgrade the recoil spring, although it is recommended.
I do carry +P as a defense round, have trained with it, and have always carried it since I started carrying with a .45 I love the power behind the round and the damage it can induce. Now, all my 1911's are steel frame and steel slide, so take that into account. 8 rounds plus 1 of that in a mag goes a long way towards me feeling very comfortable.
The stock .45 round is great, and there is nothing wrong with it, but there is also nothing wrong with having a little bit more umph behind it when fired from a weapon that is design for it.