Ed – Sorry about the delay in getting back to you on this. I’ll have someone reach out to you directly, but I wanted to also respond publicly, not only to answer your question - but to also keep the title of this thread alive in the DR communitiy. 
We often get questions regarding our metrics versus those of other sites, and I think it’s important to note that because the consumer experience differs from site to site, the metrics also often vary. We created a document explaining our methodology last year that can be found here. We realize that our methodology differs from some, but we always try to provide the most relevant metrics that we can.
As you probably know, we don't blend our search results to cite stronger new car intention in the marketplace. We know were a leader in the new car market vis a vis other brands. The request to break out Used VDPs specifically is a recurring request and one we hope to address within the next few months, and we’re also looking at a way to report on both unique and repeat used-car VDP impressions, which will hopefully be implemented sometime this year. Ultimately, we feel strongly that there is value in knowing your total number of VDPs, as repeat VDP impressions indicate a greater intent to buy. However, we recognize that it’s not always easy for dealers to measure their performance in a uniform way across the board and hope these changes alleviate those issues.
Questions about new-car metrics, on the other hand, are more difficult to answer at this point because we are two weeks away from rolling out the first wave of changes to the site experience for new-car shoppers, as well as launching significant enhancements to our online ad package.
In the research we’ve done around the new-car shopping process, we found that consumers care about more than just price – they’re evaluating your brand and reputation. Our goal is to align the experience on our site with that real-life behavior, giving you much more power to communicate your brand’s value and reputation to shoppers on Cars.com beyond a specific vehicle in your inventory. From a reporting perspective, that means that VDPs aren’t telling the whole story – how your brand performs in terms of exposure and engagement matters, as does how well your dealership stacks up against your competitors. Our goal is to offer metrics that tell the bigger story with the new Market Intelligence Report, which you’ll hear more about next month.