I don't see one of those little all-in-one scanner/printers being very useful for scanning car parts. The sort of trim pieces the OP is talking about are not going to fit in the small part envelope they've got. You're going to need a different sort of scanner, or to use a service bureau (which can be costly). Once you've got a scan, even a cleaned-up scan, it's not likely to be perfect; there are usually some artifacts from the scanning process that are introduced.

If you're trying to reproduce mechanical sorts of parts, there's a reverse-engineering step that's advisable, where you use the scan data to create a clean CAD model that retrieves the original design intent. That way, holes will be truly round instead of irregular, and other features will be similarly accurate. Software that does this is available, but it's not cheap.

Conditions inside a car, particularly in areas subject to extremes of climate, are going to be hard on 3D printed parts, which tend to be based on low-melting-point thermoplastics. Temperatures in excess of 150F, which can occur in cars parked in the summer sun, will degrade many plastics, and freeze-thaw cycles aren't good for them either. There are also some issues to research when considering the adhesion between the plastic surface of your printed parts and the paints and/or flocking you plan to apply, particularly if these surfaces are subject to wear.

So yes, this plan is feasible, but it might not be economical.

Andrew Werby
www.computersculpture.com