The material process for the Zonda will be different to yours as the person is using Octane to render instead of cycles. If you wanted maybe you could try it?? 
But apart from that, I can’t be much help, Sorry
haha i asked you in your post already about the material but it would be cool if i could make a replica in cycles with bumpmaps.
did you use integraded blender textures or textures from octane or own ??
here is another render of my car.
im planing on retopologising another time but before i do that i have to understant supporting edges, so if anyone of you know step by step how to do it, Need help, even tough it might be very simple but in none of the tutorials ive found was a hotkey or step by step description.
I nearly finish the back of the car.
I still have some problems with the Mirror- and subsurface modifiers.
hope you like it 
What issues are you having with the modifiers?
EDIT: I think I see it. Make sure you subserf is after your mirror modifier in the stack.
its still like rounding the edges off which are in the middle.
you cant see it very good but the issue is still like a problem.
and stacking the moddifiers in a different order wont make it better (i tried it)
In regards to the middle edges rounding off, if you go into edit mode and edge select mode, select the edges next to the corner you want to square off, press ‘n’ and set mean crease to 1
Hope I helped 
Oh and by the way, the lights look loads better now !!
I wouldn’t use creasing. It probably won’t be bad for this, but if you have plans on using the model in anything but Blender, it will cause issues. It also usually looks much worse than proper holding edges. It’s not exactly bad here, but it’s a bad habit to get into.
@Jeroe could you post a screenshot of your modifier stack?
here is the material stack of the car 
the edge creasing worked very well. thanks for that tipp it realy helps me out with many Problems i had
Wow, I said material stack. I can’t believe myself. I meant modifier stack 
The mirror should be at the bottom. That should fix it. I would also enable clipping, and then grab all your edges in the center, and move them towards the center. They should then snap there. You then shouldn’t need the edge creasing.
all right, thanks.
it works pretty good now. 
new render is coming soon
im nearly finished with my Project
just gotta do some new Scenes and tweeks
if you have any recomandations feel free to comment
here is another render with filters
my best render so far, still some tweeks needed but i guess its getting closer and closer to the finish 
hey guys.
im on my final render but i just cant get the result i want.
do you guys have any ideas what i scene or theme could use for my final render ?? (no foliage except trees)