I like silenced pistols. Since Glock doesn’t sell threaded barrels anymore, I had to find another source of sufficient quality for mounting suppressors on Glock 17. A friend started eleven with 5-inch G34 barrels and threaded them 1/2×28, standard for US sound suppressors and flash hiders. They cost $230 shipped, $12 more with a thread protector. If interested, email Hermes at email@example.com
If you are still waiting for a sound suppressor, extended barrel gives about 50fps extra (or as much as going from regular to +P ammo would). It will still fit any open-end holster. If you live in a no-suppressor state, you can still gain a little velocity and a lot less flash with a flash hider from 9mm AR. Functioning wasn’t affected, other than a slight decrease in the muzzle rise.