Don't change anything for now. Be patient. What you need is a SZ dual cat back. If you change now, you'll have to do it all over again a few months from now when you settle on what you really want. Post you request on the "Need Parts Forums" here and on other Z32 forums. Request a good stainless/alluminized steel system. Someone will have one for you - I know because I went through same process and there were several offers that came my way. I ended up with a dual round tip SS SZ cat back system and I love it.
If the car doesn't have one already, also plan on a good intake system if you eventually go non-OEM on the xhaust