My two cents. The only useful thing silencer does is removes your red dot from minimap when you shoot. Pistols' effective range is so short that it doesn't matter, enemy will just turn around and see you because you will be close, he won't need minimap detection. Ofcourse, other enemies will detect you, but we're LA, right? You can be gone by the time they arrive. And pistols are not very loud as they are.
Suppressors also start damage drop off earlier and maybe cause it to drop faster too. Pistols actually do a lot of damage per shot up close which drops of dramatically and a suppressor will make the 'high damage' zone smaller. If you haven't got it already, I would spend certs earmarked for the pistol on the laser.
The description for the Suppressor on pistols does not list the same drawbacks as suppressors on other weapons provide, which would lead you to believe that Suppressors offer no drawbacks on pistols. Whether this is true or not, I couldn't say.
I personally have both laser and supressor for my Rebel and it is great. If I'm using a pistol, odds are good I'm out of EVERYTHING else, and need every little bit of help I can get. I've gone on stealth killing sprees as an HA with the rebel, and that silencer has really made that possible. (The laser is also very important though.) The big deal is that if I'm out of ammo in front of the enemy lines, I just double back to get more. If I'm out behind enemy lines, well... time to do as much damage as I can before someone kills me. Staying off the minimap is crucial to making that work.
I personally always roll with a silenced pistol on just about every loadout for every class. Even for LA, it's still very handy, especially if you're using a shotgun for either CQC or slug sniping, allowing you to still maintain stealth for some situations. I find it a great tool for clearing out snipers from hills or AV turret engineers etc. As well as anyone else not paying attention. A couple quick shots then a melee to finish they die before they can react, and it allows you to not spook any nearby snipers etc. Yes, you can escape fairly easily as a LA, but personally I find it much more effective to keep them unaware to my presence as long as possible, allowing me much more free kills before a firefight erupts. On my SMG and Carbine I almost always have a silencers as well and the damage dropoff doesn't seem noticable. Mostly because If I'm at medium to long range up against something that can kill me faster at that range, then I've done something wrong. The only time I should ever have firefights at more than 50-75m is if I'm slug sniping. I'm much better off beating a hasty retreat and approaching them unawares from a different direction and within a more optimal engagement distance. Unless I'm using my Solstice SF with GL, then I just fly up and fling a grenade their direction instead.
I did some tests in VR and it does start damage drop off sooner, like with other weapons. I don't think it does it a huge amount, but it will make the difference of one bullet a few metres earlier than without.
I personally don't like using silencers, the trade off in bullet speed is a big deal to me. I also don't like the quieter sound as it screws up my aim.
