2017 Toyota 86 front pipe to mid pipe donut gasket
 

Hello friends,

Last night put a cat back on my car, when I took the stock exhaust off no donut gasket. So when I put my hks cat back on there is also no donut gasket now. Is this a problem? Should I pick one up and slap it on?

If the HKS exhaust has a donut gasket type flange (instead of a flat 2.5" flange), you'll need it or else you'll have exhaust leaks

You sure it wasn't wedged into the oem catback? maybe check there and see if it some how slipped off and was stuck in the catback piping. If not, you'll need a new donut gasket to prevent leaks.

I didn't see it, any chance it is like melted on to the front pipe? front pipe to mid pipe looks like it has a little bit poking out with a black tip that looks like the pictures of the donut gaskets and I haven't noticed any leaks yet so I think that's the case

The a used donut gasket will probably look like it's part of the pipe when you look directly at it. The front pipe flange mating surface should be flat, if it isn't then there is a donut gasket attached.
I took mine off at 20k KM when I did mine and I had to pry it off with a flat nose.

Cool then it was stuck to the front pipe and I have one! Thanks for the help