The first thing you need to determine is, does your pistol use a ramped 9mm barrel? If it does not, and I think this would be the case with a factory stock Colt, then you will need to avoid ramped barrels from any manufacturer. To be sure, when you look at your barrel is the bottom of the barrel throat round, or does the bottom of the barrel project down into the frame (i.e. a ramp up into the chamber). If there is no ramp then you still have a standard profile barrel and most any "Drop-In" barrel may work for you. Though, you should be aware that there are enough variations in how slides are machined that a drop in barrel may not drop in perfectly, some minor fitting may be required. To minimize this stick with barrels from the major name providers like Ed Brown, Wilson, Nowlin, or Kart; there are a couple of others but they escape me right now.
If the barrel has a ramp, then you have a couple extra things you need to check. Because different barrel manufacturers may use different width ramps and you will need to make sure you get the right one. The best way to do this is the measure the width of the ramp in your pistol using a set a calipers. Measure a few times so you are sure of the width then check with the provider you are interested in to see if they offer a barrel with that width. If they do not, find a different barrel provider as a ramp that is too wide will not fit in your pistol and too narrow will probably have feeding issues.