Port that puppy and be proud!!!!!!!!!!!!!
I carried a Glock 22C as part of making a living for a few years and was never once concerned about extra noise or flash. During the bright the flash is a non issue. Since you should be wearing ears when you practice the extra loud should be a non-issue. If you are shooting in the dark you can select ammo with low flash powder which makes the flash, again, a non issue. If you are shooting in the dark and just for fun, get yourself some ammo with extra flashy ammo and have fun with the flamming bunny ears of doom. If the ports are angled outboard like the ones on the Glocks you won't even really see the flash if you are actually focused on inportant stuff like your target and the front sight. Even if you are looking for the flash its not nearly as good as the cylider gap flash from a big wheel gun launching full house loads.
So how about losing velocity because you've effectively shortened your barrel. I'm not sure if that's a straw man argument or a red herring fishing expedition. IT'S A PISTOL!!!!! By definition it's an underpowered, inefficient, ineffective tool regardless of caliber (sorry 45ACP fans but its true) carried because rifles and shotguns are too big and heavy for everyday wear and don't serve well as fashion accessories in most social settings.
If you are worried that flash might hinder you during a defensive shoot you are worried about the wrong thing. Running, hiding, shooting back and not getting perforated are all a lot higher on my priority list than potential hearing loss.
"But Grumpy" you ask, "Won't the bunny ears of doom give away my position?"
"Dude", I answer, "You are in a pistol fight. The other guy already knows where you are." You really should have shot the other guy firstest with the mostest or better yet, shot that sucker in the back when you had the chance.
At the risk of being a bit over board here, I suspect that ported guns might be a bit out of line for offensive shooting. Of course if you are shooting offensively and you are stuck with a handgun, wouldn't you be better off slapping a can on that sucker and going for the back of the head shot?