The Saturn Kappa is expected to be there. I have seen a couple of different publications indicate that it would be in attendance.
The ’05 Boxster should be there as well. All the major publications have been putting out preview stories already. Its not going to be much of a secret by January, but I cannot imagine Porsche not having it there.
The Miata, unknown. Do they intro it at Detroit? Do they wait until Chicago in February? Do they wait for the next Tokyo show for its worldwide into? Since it is still off in the future somewhat, and they have been quiet, I wouldn’t be the farm that it will be there. It is possible they will have it, but certainly not a lock.
I wouldn’t expect the Vauxhaull 220. GM is generally not in the habit of showing Vauxhauls and Opels in Detroit. Last year they had the Vauxhaul VX Lightning Kappa platform based roadster concept along with the other Kappa vehicles. However, that may have been more to judge its styling for potential use as the Saturn Kappa roadster than to promote Vauxhaul in any way.