Here's all the body accessories we have for the Gen8 in one parts tree to save some $$. Shapeways has a minimum charge per piece, this is treated as all one piece.
You'll get 2 x Windshield wipers, 2 x door handles, 1 x gas cap, and 1 x rear handle, with some washers.
You'll have to snip the parts free, poke some holes in the body where you want them to go, and use some M2.5 screws to secure.
The windshield wipers will be held in with glue. Goop is probably the best. Keep the hole small so it's a tight fit.
The tree comes with some washers that go inside the body to help keep the screws from pulling through.