I think you need 3DsMax or it's open source cousin Blender
OK 3Ds Max, Brazil???
3dsMax 8 and brazil render plugin. Never got old version Brazil to work in MAX09 and the new version is not doing its job with the SCENES.So that is what you need.Then you need some help to use it.But get it first.
http://www.splutterfish.com/sf/WebContent/IndexApparently the "Brazil Rio" is free but i think its not enough.Also you cant use the latest 3ds max cause the brazil dont work on it if i remember correct,cant remember which version works though.. shame that Byron is away, he would know more.
Does render mean to see the changes in another program which u have done or is it maybe to paint the car in this program?