Glock 17 + FO sight + grip tape + trigger tune = IDPA SSP + USPSA Prod.
You could dress it up some more for IDPA ESP but it might push you out of USPSA Prod into Limited where you would be at a substantial disadvantage shooting Minor.
Major accessories, holster, mags, mag carriers, ammo, shooting class.
Sorry, Strafer, you can't shoot a 17L in IDPA at all or in Production.
If he doesn't mind us spending his money the only real gains in a new Glock would be with a G34 or 35.