It's a nice looking brush this, maybe more of a toon, but overall it looks nice.
If we start with the design of the car, well what can I say. hehe. You havn't done much, but I am also guessing that the main idea with the chop was to practice your brushing. But you have changed the rims, and I think you made a good choice there. They are not as racey, a bit more show, which makes the car a bit more ricey, but this is still a hardcore Skyline so you are off the hook. Hehe. I also think you might have lowered the car a bit much, and I'd liked to have seen the rims closer to the wheelarches to give it more of a wide and racey stance. Now it looks a bit odd.
If we move over to execution I think you have done some really nice clean work on the brush, however maybe a bit to clean. The refs look way to harsh and give the car a toony feel. The biggest issue with this chop is however that you have put the car indoors, but you still have the outdoor reflections. What had been a better solution would had been to have rebrushed the entire car without the refs on the side (which are the most clear that they are outside refs) and then brushed on new refs with a car in a garage setting as a reference

Sort of blend the two pics together.
But nice quality brushing. Keep it up, but maybe add some mods to the body next time!
Cheers!