Black one on the left looks good, Not so fond of the Red. Red is just way to saturated. Look at the Red/Green/blue channels independently, the car will pop like crazy
-Img Below At the top is your current red channel, Compared to the Blue and green channels below it.
The image below the color corrected audi is the Red channel of the new image. notice how it resembles the blue and green channels of the first image-
Was the car modeled in Houdini or imported from maya, 3d Studio ect?
Also I'm curious as to how you're compositing this into the background image. Are you using Houdini's built in comping or something external such as nuke/Shake?
Thanks for comment, model is import from Maya, And image is render from Mantra, no compositing was done, i save image from Mplay nothing else. and for Red color i just try to see how is going to look, its my first time to play with PBR and car rendering.