Im not a rendering expert myself so i wont go into detail, but i can tell you as much as i at first scimmed through the post without really looking at it. Then clicked on one of the images to inspect it a little further.
I think it boils down to lack of proper lighting and reflections. To give you an example, im going to compare you to this guy Corvette Stingray, which is by NO means fair considering the budget of this guys project, but i’ll do it for the sake of argument.
The amount of details that catch the light and reflection makes it so that you spend a lot of time looking at the model, and simply admiring every edge. You can scan your entire model and you wont find any areas with decent rim lighting or eye catching reflections. Only simple ones which are easy to ignore.
Also look at the tire, it catches the light, and displays it shapes. This is not such an important thing in this guys’s project, but its something that is EXTREMELY important in your project, because the wheels are such a big part of the model.
Your tires look completely flat.
this could serve as inspiration. Do research specifically for the tires.
Here is another example
Try to not look at the car at all. Focus only on the environment behind it. There are decent shadows, reflections, and a nice variation of colour. Your background is very monocromatic and has no reflections to speak of.
This is something you can get away with if you have a very interesting model, but you dont. And thats not your fault, you can only get so far with a McLaren in terms of “cool” factor, so you have to present the model with every tool you have to make it stand out.
Another thing i noticed while doing research was that a lot of McLarens use the same texture style. The white and red that you have, and another with black and orange. Keep in mind that in order to stand out, its not always best to make whats already out there, but instead create something of your own.
Which of these cars stand out the most to you? I think you get the point.
Having a realistic version is always good to stay authentic, but feel free to re-texture one separately and go crazy. Add neon lights and epic decals, take inspiration from videos games such as Rocket League or other surrealistic car games.
Notice how he has a lot of different versions. One white, yellow, red, and blue. Everyone has a slightly different taste, so try to appeal to as many as possible with little extra effort.
Side note, i didnt intend to go too hard on you. What you have is good, but there is so much room for improvement. I really dont want to discourage you! Nail this and you may even make it to featured. There is a lot of potential if you nail the rendering.