First: post the HR to can see datails
Second: in the low resolution, only i can see that you used the same rim, in front and back, because of it, the rear looks flat.
TebiDesign said it all for me really, nice start though. You should slam that badboy to accentuate the wide kit
Tebi - from the low resolution of the chop in your signature, it would appear you have also used the same rim twice, thus making the rear one appear flat