Another CAD data file website is:
www.3dcontentcentral.com, and there is probably a bunch more.
The thing that I find is, there are plenty of models of cup holders, and trinkets, and other such stuff, which is great and sometimes very helpful if you're looking for something generic. However, if you're looking for a very specific part, that fits exactly into what you're working on, the chances of finding that are much more slim. This is where you need to make your own CAD model. The steering column bearing cage is a good example of the latter.
3D printing an inner grill is probably not worth it, unless you wanted something custom. 3D printing is not really cheaper or easier than buying something off the shelf, at least not yet.
Blender is a modeling software:
www.blender.org
Another recent CAD software (that looks promising) is called ONSHAPE.
https://www.onshape.com/cad-pricing
They offer a free version, which has good functionality much like SolidWorks. Good tutorials for those that might want to learn.