hehehe - I thin I agree with Linuh this time, it is a little bit small - it's nice to be able to zoom in, but you can't really
You say the base is only 1280px? Then as you are rebrushing you should resize it

But basically, try to aim for 1600px as a minimum really
Anyway - onto the chop itself:
I'm loving that kit that you've added - I always applaud any kit that makes the car visibly different. It is slightly off at the rear, but heyho, it still looks cool
The brushing is very nice too, but I think a little more work on the side would make it even better - compare the reflections you have to those on the base, they should be similar (i.e. a horizon line of some sort)
But this is actually a very nice chop overall, so well done
