Last week I took my car to get fitted with cat back system, but
The doughnut shape gasket that goes between centre section and
Cat pipe crumbled with rust, the garage fitted one but said it was slightly to big
When I drove car away it felt and sounded great, but
Since then it's blowing and the car has lost a lot
Of power, do u think it could be this gasket? Is it worth
Getting another one and going back to get it done again?

 

It's a wrx bugeye uk 2001 , is there a name for
This particular gasket? Is it a standard size wanna make sure I get the right gasket