My 88 vert makes a hissing noise out the mufflers when accelerating. I don't hear it at a constant speed. The cats are gutted already. Just wondering if the stock mufflers are prone to collapse??? Trying to hold off on a new exhaust system until I do a TII swap. The TII donor car I bought has a set of those twin tipped "monza" mufflers on it. I think they are butt ugly but they might have to go on temporarily.