"most shotshell powders complete most of their burn in the first eighteen inches of the barrel" is what I found so apparently porting is 99% there for the "cool factor" and creates the "pain in the ass to clean factor'. Debunks my friends thought that porting affects anything at all.
Myself I could care less of the noise but I do care a lot about the noise if it is due to a load that is potentially dangerous and I here of a lot of that.
Most of all for some reason I'm killing them in game on 3rd and 4th shots out just off the ground from the 27 but with my bt99 plus with the same chock I just take it out of one and use it in the other. Same length barrel also. Not the same results however.