As I've written several times full brush is not for me for sure, I'm not so skilled in this kind of work so I do what I know I'm capable to do at my best... for this reason I brush only little details and not all the car.

Anyway gold is good but imho this color is more aggressive:

But it looks too desuterate.

that bg is off mate, also you need new indoor reflections, or make it outdoor, the rest is looking very very cool, keep it up
i was enjoying the gold color, that gold color in a outdoor bg, maybe a hangar, or a dock would be killer

Yep RC, I've just changed the colour with another one.

Huge looks better now the BG?

Probably looks better in this way... fixed the right side of the bg

I agree with Hugo
For this background, i think the floor under the car is ok but behind, yeah, it's completly off

Ooook back to gold
And now I need a new BG

So this one can be ok?

He's hit the nail on the head. Reflections aren't all one colour, there needs to be different shades, colours, and more contrast. Use reference pictures

Just to having fun