I heard of someone I think in Arizona that does trigger jobs.  I think it is accuracy speaks.  It is a single stage trigger.  Can this be done to a colt with sear block? large control firing pins.  Is it worth it.  I think it is $165.  Where to contact the person if it is worth it.  thanks.

[url]http://www.accuracyspeaks.com/index.html[/url]

I think he will install the trigger for you for a small fee.

E-mail him and ask about prices and whether the trigger will fit in your lower. I know he sells the trigger with large pin or small pin, but I don't know how the sear block would affect the fit.

Derek Martin @ Accuracy Speaks is one very good guy to deal with. Is the trigger worth it? HELL YES! Derek is a very serious shooter, not some marketing guy for a big company like Colt.
I'd try just ordering the trigger and going with the enclosed installation instructions. They are very clear (clear enough that I could do it: meaning clear enough that a labrador retriever could do it).
Good luck.
SD