Ok, first off, shame on you for not saving multiple copies of your 350z before continuing on hard stuff like doors, windows, grills, ect. That was coming along nicely(another helpful trick that you can do in the future to prevent you alot of heartache is to use the new Edit Poly Modifier in 3d studio to give you some flexability. The reason for this is, the new modifier lets you stack them and make changes on each one, if you go back down the list to the previous edit poly you were working on, it will show you the changes that you made on that edit poly and the ones before it. That's just incase you didn't know that helpful trick.) Ok, anyway, to the material, first off go
here and follow this tutorial exactly. It will give you an amazing base material. After you're done with this, you can edit it to your own wants/needs. You can change the color/what not. Also, you can change the specular from none to noise or cellular(when you do this change the size value from 25 or whatever the default is, to something small, like .25, this will give you the illusion of flakes in the paint.) Anyway, from there, you just go on and do what you want to do with it, if you want to see what it looks like, check out my
Fiat 500. Ok, and now for the grill material. The grill material I'll have to get back to you on that one, I know that the metal material on my bumper and rims looks pretty sweet, but I don't have it in front of me to tell you how I did it, I know that I used HDR in it's creation. But for now, that's what I've got for you. I hope that this all helped at least a little.