A friend took the magazine disconnector out of his Mk III and found the trigger pull light enough.  If you don't, they cannot be reduced as much as a 1911's by sear work.  I bet Mr Camp had a number.  The wider trigger will improve the feel but not actually change the weight of pull.

If you have an original style with the teeny single safety, I think an extended single safety would be very desirable.  I don't think you need an ambi for IDPA.  But the Browning type seems sturdier than the kluge marketed for 1911s, if you just want one put in while the gun is in the shop.