how to make one camera see different textures

What i would like to do is have one of my cameras(with a small view in the corner of the screen) see everything in and Overdraw texture. Is there anyway for the camera to just see different textures? This is kind of hard to explain... One thing i was thinking of doing is duplicating the car on a different layer and using a depth-only camera to see that, but that would double the amount of faces which would slow down game performance a lot. I need a way to have two different textures on one object and have each camera see the different textures.

Thanks a bunch!
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FPSyndicate