I have at probably close to 10,000 miles on my borla and have no problems, nor have I noticed my tips "vibrating". But I do have an oil change coming so I'll take another look.

IMHO, flanges or slip fit clamps. I see no difference in design in terms of noise reduction or otherwise. I have no binding in my Borla and didn't have to pry or coax anything in order to bolt it on.