Well not instruction sheets, you see people use these sheets to model 3d models. Not real models and people find car kit models are the most usefull, especially Tamiya kits people like those a lot. People model cars for games, and also just to render. Here are some pretty high up example of what people do when they have blueprints to cars they really enjoy.
http://www.3dshop.com search vehicles and see some pretty amazing work.