i agree the colours are really nice here! the only things that i think could be improved are a matter of consistency. having a lineless background mingled in with a lined foreground feels a little odd. i think the panel will feel stronger if you line the background elements too, especially in the first panel where there are lots of different colours and bg features sitting together. using a brush which is 1 or 2 px smaller than what you used for the foreground will keep the foreground as the focus, or alternatively you could use coloured lines for the bg and keep the foreground lines black.
the red car is a little too vibrant, and directs my attention towards it. and when i look closer at it, it feels a little sloppy (partly because the lack of linework). so you probably don't want everyone's eyes drawn to that unless it's the purpose of the panel! i'd suggest a colour more neutral, off-white or grey, or something tinged green or teal to match the colours in the rest of the scene.
the last thing i saw is a little nitpicky, and because i tend to hyperfocus on text bubbles.. but yours have inconsistencies which can be bothersome. the spacing around the text is uneven, and sometimes too close to the edge of the bubble. the positioning of the bubble from the borders is uneven too. i don't know if this is something that concerns you at all, but i think adjusting this could really improve the page!
i hope this stuff helps and doesn't feel too nitpicky!
