It will depend on the exhaust, what brand/style have you purchased?
Generally you will need these:
Turbo to Downpipe - 44022AA180 - $18.53
Downpipe to Intermediate - Stock donut or 3" flat flange?
Intermediate to Muffler - Stock flat or 3" flat flange?
We stock two different styles of 3" flat flange, either the cheapie Vibrant Performance for $8 or GrimmSpeed multi-ply metal gaskets for $18.99 each.
Either way, we should stock whatever you need for whatever kind of exhaust you have.