Are there any problems associated with adding different equipment to a Colt SP1 lower (different upper, trigger parts, etc)?

I believe that the front pin hole is a larger hole than current uppers utilize.  Does this cause a problem with adding different uppers or is there a fix for this that works well?

What about adding a collapsable stock to this lower, or internal differences in the trigger setup, etc...

I want to make sure that I still have the ability to alter the weapon without running into a brick wall.

Thanks for your help.

For a small pin upper all you need is an offset pivot pin and you will be good to go.  The trigger setup is milspec small pin.  A collapsible stock should not be any problem either.  IMO, The most I would do to an SP1 is swap uppers. That is all.