Here's my CL history.
I used to post to CL via sexy templates. Jealous sellers would blackflag me every chance they get. Overall, CL results were fair, but I wanted more.
Next, I decided to follow the CL tradition. I dropped all templates with graphics, used only 2 car pics, used basic VIN features, added one paragraph of comments, linked to VDP and phone number. It worked! The traffic homesite from this ultra-basic layout was far superior as compared to the polished templates. My manual CL poster was an intern that just went back to college, so I gave CarGigi a try.
The Cargigi platform has a cool traffic analysis tool, but the lead counts are way off and traffic to my site is way off. CarGigi converts all content into an image, then posts it to CL. I dont care for that process.
IMO, cargigi spends so much time trying to outfox the blacklistings, they totally overlook the conversion metrics (lead counts, traffic to dealer sites, etc)