Hissing from hfc, is it a rumor?

Popwarfirm2

Hey everyone:

I have heard rumors that if you replace the hfc, or take out the oem, that you start hearing a "hissing" sound. Is this true?

I have also heard that the problem could potentially be an exhaust leak. If so, would it be possible to put an exhaust gasket?

I say exhaust leak because it seems like there are those chappy flanges on the end of the parts...maybe it could be it. If this is the case, should O just buy my own flange and replace them? (maybe a v-band clamp?)

Sorry for the long post with multiple questions, I just want to find someone who has had experience with this type of problem before I take the plunge.