I have never heard a factory 45 thread on can that is as quiet as
a integral yet, and I have been to many silencer shoots.
The integral can on my 45 is 13" long, if you want quiet with
a thread on can you will need a big custom built can and a realy short
barrel to keep you OAL 16" or less.
The best thread on factory 45 can will cost more than a integral and still wont be as quiet.
No need for a SBR if you go integral so that will save $200 that can be
used for the build.
I have many cans for many calibers so my vote is for the integral
if you want a short package and quiet.