I'm rather new to the 1911 world. I would like to replace the factory solid trigger with a three hole type on my C3. Are these triggers drop in or is it more complicated? What, if any concerns are there with this type of change. For what its worth, there are no issues with the trigger. I simply don't like the look of a solid trigger. What is the rating of the recoil spring in the C3 (18#, 20# etc)?