This is fantastic. I'm working on something similar for other product categories. One rule of thumb I'm going by is to show as few results to the user as possible. Shopping sites often offer so much choice that the user is too paralysed to make a decision.
I'd change the default setting from showing all brands to 2-3 at most. Simple sliders to narrow down the price and mileage range would improve the usability a lot. Plus, if you're presenting any information as shape, colour or size, you need to show a key which explains what it means.
You've done remarkably well to put this up in a weekend. I need to pull my socks up and release my v1 asap.
I'd change the default setting from showing all brands to 2-3 at most. Simple sliders to narrow down the price and mileage range would improve the usability a lot. Plus, if you're presenting any information as shape, colour or size, you need to show a key which explains what it means.
You've done remarkably well to put this up in a weekend. I need to pull my socks up and release my v1 asap.
Good luck!