Well, I would say the interior look is defined be the money you want to invest.
Design wise the Z-Art interior looks pretty good almost OEM.
Mine is also seal gray inside, and a little alcantera "could" be the icing on the cake.
I will post a few pics on the seal grey thread soon.
Recommendation: If you find someone, who will prepare/install a Z-Top for a reasonable price...DO IT.
If you have a "challenge accepted" attitude, it can be a manageable DIY project.