You will not want FDM printing if you want a good surface finish right out of the printer. Some sanding, filling, painting, or other postprocessing will likely be needed. You may want to get a small sample part made and see what you think before committing to something the size of a pillar pod, regardless of what type of 3D printing technology you end up using. Might not be anything that a little sanding and some SEM texture spray can't solve before painting to match the interior plastic.
Material choice will also affect surface finish, and of course the color and mechanical properties. ABS or PC-ABS will be the cheapest choices.
FDM also isn't especially strong because of the way the material is deposited. Unfortunately that's also the cheapest method of 3D printing for something like that, so you may need to step up to a more expensive process like PolyJet or SLS.
Most all of the home printers are FDM, to put that into context. They're the type that feed a spool of plastic line in, and work like a hot glue gun. You can actually do a pillar pod with a smaller printer by doing multiple smaller pieces if you add joints to locate the parts to each other and join/bond them together. Many prototypes are done that way out of necessity.
Whatever you do, think about the part in terms of an injection molded part, where you want the least amount of material. That means thin sections and using things like ribs to add local stiffness instead of making things thicker, etc.
You're paying for material and for machine time, so the more material volume and the longer it takes to print something, the more it costs. Make no mistake, this is going to be a fairly expensive part. It may be only a few hundred $$$ for FDM, it might be a 4-digit number for PolyJet or SLS depending on material volume.
Also, you're going to need a solid model of the pillar pod, and you haven't mentioned if you have that already or need to have that created. If you want to have someone 3D scan an existing part and then tweak the file into something usable and printable, factor that into the costs.
Shapeways is fine, and I've had okay luck with them but I normally only use them if price is the most important factor. Depends on what you need for accuracy and for material selection.
Oh, make sure whatever material you use has a high enough heat deflection temperature to handle the sun baking in through the windshield.
Sorry, I start to ramble sometimes....
