Works well in SD but at export with the same settings, i'm loosing quality.
Should I work and export in HD or Work and export in SD?
Its not a ratio Problem
How should I import the clip?
Don't know if the problem is at import or export.
The final intended destination might help you decide workflow. With the file being 16x9, I would bring it into HD project and export 16x9 rather than be confined by anamorphic ... especially if this is for web/computer use so it can be progressive vs. interlaced .... I might add that I prefer to do this even if for DVD, at which point you have the option to make the DVD progressive or interlace.