P7M8
I don't have my rule book handy, but I am pretty sure it will have to be shot in ESP. 1911's are CDP, so you won't be shooting against them unless they are something less than .45s.
As far as competition, the problem is that you have an 8 round mag in a class that allows 10 round mags, so, depending on the course, you may wind up having to do extra reloads compared to everyone else. That being the case, it is not the optimum IDPA gun, but IDPA is a great way to keep sharp with it if you buy it as a carry gun.
I got really curious and bought one and kept it long enough to shoot it a bit. It is really a novel weapon, a joy to shoot and own (but not to clean). I sold it after I shot it awhile, it didn't really fill a niche for me and the manual of arms was so different than what I carry normally.