I know that this is an older thread and the title is: "USPSA Production Race Gun - Modifications to a Glock pistol" but the origial op's first line reads:

"Last year I got into competition shooting with a focus on USPSA, IDPA and 3 Gun."

So I have to make a comment and say that if you do all of these mods you won't be in "stock service pistol" in IDPA any longer. As a guy who shoots IDPA and USPSA I usually set up my gun to the IDPA rules and use the same gun in USPSA production, even though I shoot more USPSA than IDPA.

I did like the above write up and wanted to thank the OP for a good review of the USPSA rules.