Just fitted the SS downpipe, with Magnex centre section and I can hear a leak at the joint.

Do I need to rip the doughnut off the original downpipe and stick it onto the SS one?

Any speedy responses will be very helpful!

Yes

Cant get much quicker than that :)
BTW if you cant get the old one off go to a local quick fit or such place and blag one, hell of alot cheeper than going to Subaru

Thanks for lightening responses!

I managed to get the old one off - not particularly clean so may pop into Kwik Fit and get a new one!

(I'm such a doughnut!)