So this is the situation, I am buying a used APR downpipe off of a member from vortex that has the APR turboback exhaust system.
My question is what else will I need to get to make sure the downpipe will fit my stock catback? A reducer?
And more importantly, will I need to trim the downpipe to fit my catback? If so, do you recommend doing this or is that just a bad idea? Or maybe should I trim my catback to make it fit?
Has anyone else done this before?

Any suggestions would be greatly appreciated.
Thanks.