Ok, here we go. Either IDPA or IPSC (USPSA) will work great for your Colt. A few things though. You cannot have or use 10 round mags in IDPA in a Colt 45ACP 1911. You will have to top off when you start out, but your gun will not fit in the IDPA box with an extended magazine. For IDPA, you will need (3) mags, for IPSC you will want (want, not need) at LEAST 4 mags and pouches. Dont bother with the Tungsten guide rod, as it wont make that much of a difference anyway, will save you $50.00+, and you cant use it for IDPA. Keep it simple and have fun. Dont get caught up in all of the "you have to buy this" stuff. It wont make a difference. If you want to buy something, get good sights. I would suggest a Heinie Slant Pro rear and a Dawson Fiber Optic front. But you dont need them. Check with the local club you will be shooting at to see how strict they are on the holster rules. Alot of clubs will let you use the Uncle Mikes $20.00 holster.
A couple of quick tips for you, dont shoot with your ears. Everyone tries to shoot the speed and cadence that they hear the person before them shot. Dont do it. Shoot when your sight falls back into place and no faster. Go too fast and you will drop points. Makes sure your mags are seated in your pouches with the bullets facing forward....trust me on that one. Dont load until they tell you too, and dont turn around with your gun in your hand. Just have fun. It is very addicting.
Mr. Pitiful