I put on an exhaust on my friends car today. Its a stock 2004 wrx. She just wanted more rumble. Its an N1 clone catback. Cost $130 so I expected some issues, but it fits good actually. The kit came with 4 bolts and 2 nuts. I omitted the original spring bolts since they broke anyway and the kit seemed to not require them. It came with 2 flat gaskets. The downpipe connection had a concave area for donut gasket so I used the donut gasket. It was still really good.. When we fired it up, it was slightly leaking from that connection, but it was solid and quiet enough for now. She wanted to go for dinner so I just pulled the jacks and off we went.

 

what should I do to stop leak? The system went in fine. One mis alligned hanger bracket causes everything in the rear to be off enough bolts wont clear the rear connection so its only hanging by one of the muffler hangers until I can adjust the rods position with a torch. But that's the only issue and its a small one. It still has 3 hangers fully seated

there's conflicting info on the donut gasket. Should it be omitted in favor of flat gasket?

Use a Subaru donut gasket. The cheapos don't fit right and always leak.

the donut right? I think for the rear connection, ill pull the rear hanger off the muffler , loosen the bolts and tighten them back up. I'm thinking it will center and all hangers will fit.. I shouldn't need new spring bolts tho right?