I've heard some don't run a gasket at all for the turbo to downpipe connection, while others use a copper gasket-maker or stainless pre-cut ones.

Thoughts?

 

I would run one. The Miata crowd are the only ones I have ever heard about not using them, or maybe I just ignore it when anyone with any car (Turbo or not) mentions it, because its asinine.

ATP-Turbo sells some quality steel gaskets. As long as the faces of both parts are flat, they will work great. If they aren't flat, no gasket will work, and will likely always fail.

 

It's the manifold->turbo gasket that we ignore, not the turbo->downpipe.