IGES or STEP importing from CATIA V5 R16

Try exporting the CATIA model as an ACIS file (SAT) and see if you get better results.
To tell the truth, I've seen pretty good stuff coming out of step. In your position, the first place I'd check is my catia export settings, or possibly Catia model to see if it's meeting all of the requirements for your solidworks model. It may be that your missing parts are surfaces or other non-manifold geometry and Solidworks is set to exclude these on import.
John

Michael,

You might want to check and see if CATIA has any export accuracy settings. Pro/E has a relative accuracy setting that when lowered yields better IGES files for import into SolidWorks.

Best Regards,