Hi! I really like the front bumper you've used, that style suits the car very well. As far as making the bumper less toony, I'd say you need to remove the huge difference in tone and make the shades closer to one another to remove the edgyness of the colour transition. The bumpers midtones, over all need to be brighter where as the highlights on the top of the right side intake need to be darker. A lot more shadow is needed inside the side intakes as well, as currentntly there is to much light. Also Id say the bumper overall needs a bit more tone. Clear that up and it should look great!
Im looking forward to seeing the end product, keep up the good work!
"Never give up before you begin!"