Car Customization Demo

this is a tech demo that does the following:

• A custom surface shader which allows the player to randomize or select a new color scheme for the car. The color scheme must change both the paint and upholstery colors in a harmonious (but not identical) fashion while preserving surface details such as rust and wear. A full RGB spectrum should be possible.
• A decal system which allows the player to optionally add one of 4 different “tattoo” sets to further customize appearance. 
• A car ornament system which allows the player to optionally add one of 4 different ornaments (hood scoops and spoilers in this case). These should also use the custom surface shader.
• An on-screen GUI with buttons and sliders to control customization.
• The final car should be able to export from the “Build Your Car” scene into the “Race!” scene.