Just bought the full catback HKS exhaust and I forgot to put the donut gasket do I really need it? I didn't hear no exhaust leak.
I seen a video with another guy looked like they didn't put it on either. I still can't send the videoI think you should be okay, put it on when you have time for piece of mind. If it's not leaking though I think you should be fine. DM it to me if you have a video lol