Simple is preferred over complex. As I'm not a talented designer, I'm trying to keep the rest of the site's design simple, and it makes sense that the logo should fit with this.
The main colour of the site is #eeee00, with other colours being blue for the links, and various monochrome elements. I don't want to start adding extra colours to the site that don't fit with that scheme. If you have a great design that differs from that, I could be convinced, but it would almost certainly mean changing the main site colour.
As the site is international, any graphics of cars should not appear to be specific to particular markets. For example an SUV or pickup is not really appropriate as that's rather US centric, and likewise, a really small car is a poor fit for the US market. Car related graphics should be appropriate to all countries.
As the site is aimed at helping consumers buy a car, and troubleshoot problems with their existing car, the two themes I want emphasised are cars and trust. The logo should confer confidence on visitors that the site is a trustworthy source of advice. Therefore any playful or frivolous designs are unlikely to be appropriate.
Related to the above point, the site has a general audience, and many people are looking for sensible family cars, so anything that implies excessive speed or racing would be inappropriate.
I've included a screen capture of the new layout that the logo is intended for, and the image used as the current logo placeholder. I'd like the new logo to be roughly similar in terms of size, and due to the heading being just below the logo, my place holder logo is muted deliberately so that it doesn't overpower the heading (1997 Vauxhall Frontera Review). Any new logo should not be so strong that it dominates the heading.
I'm not too concerned about the capitalisation of Carsurvey.org. Whichever works best with your design, and I'll adjust the rest of the website to match. Carsurvey.org, CarSurvey.org, carsurvey.org, CARSURVEY.org, and CARSURVEY.ORG are all fine.
I have a slight preference in favour of showing the .org part of the site's name, so people don't go the the .com, which I don't own. If it doesn't work with your design though, it's not a problem, as even Google searches for carsurvey.com suggest carsurvey.org as what you are looking for.