I just installed test pipes on my car, and i removed the stock cat bracket. ive noticed my stock Y pipe (stock from cats back) maybe be hanging..and the flange at the muffler side of the Y pipe seems to have a 5-7mm space between the Y pipe flange and the Mid-pipe flange. Is this normal? Could this be causing this nasty hissing sound as my car coasts in gear???

If so..how do i fix it? I can't put the stock cat back on..?? thicker gasket maybe?