Two things...if you can afford 2 cans, get two cans. Waiting 6 months between having your 2 cans sucks...

If you can't afford 2 cans, get a .45 can. You can shoot 9mm, .40, and .45 through it.

And the ammo you shoot is more important to reducing the sound levels than the can or host...you can shoot 115 all day long through any can and it'll be loud...but once you shoot 147 or 158, you won't go back...

That being said...even though the sound difference is small, I can hear the difference between shooting 9mm through my Osprey 45 and Evolution 9, and I'm glad I did get a dedicated 9mm can. I thought I would be happy with a "do all" pistol can, but I'm happy that I decided to get a 9mm can as well...just waiting on the approval was the painful part and I wish I would have just ordered them at the same time.