i have been leaning to use "slip on pipes" at the collector itself, with high temperature copper RTV to hook up street exhaust systems. [after cutting off the common 3 bolt flange]
this seems to have cured the collector flange leaks that commonly show up on street exhaust systems, especially the bigger and heavier size[s].
way easier than welding on V-band clamps or misforming the collector with a stainless band clamp.
however, there has not been many miles or months doing this to see how long or permanent the copper RTV will last.