1. dont mirror the image
2. dont blur
3. fire colors on blue backgrounds are impossible
i sound like an ******* now, and im sorry for that but you put alot of time in bringing a bad result, its easy to make nice stuff with 3d renders if you know how..
this would be an annoying post if i only told u what ur doing wrong, and not tell you how to improve it.. sooo:
make simple renders, not too complicated, render the scene from some different views..
then goto photoshop, make a new image of the wanted size, then put down those renders on screen mode, when it becomes very bright, press ctrl+shift+e (merge all), duplicate the layer, mirror it horizontal and vertical, then put it on multiply...
if it gets too dark again, put on some more renders in screen or overlay mode..
you can fix up the result with the burn and dodge tool...
i hope this works, if u got questions, ask them if u like