I shoot IPSC. I do so with my G19.
I bought it from a policeman who had done the same. I added grip-tape, kept the tritium sights he'd added, but I did remove the only other accessory he had used: a mag release extension.
I took it off as the G19 is also an SD gun and I preferred not to run the risk of dropping the mag in a moment of stress.
However, if permitted in the rules of the IDPA & USPSA competitions, you might want to add one: makes dropping the mag much easier and may save those few extra milliseconds!
You cannot wake someone who is pretending to sleep. Stop pretending. Wake up.
Doubt: ...it's the only thing I'm sure of...
-Marsupials: Nature's idea of Concealed-Carry-