Yup, they're showing across all 728s, it seems. A few months ago it was a Honda ads (I think, or maybe Toyota), but those only showed in the 468s (I think). Damn my memory sucks.
And how much you get with one click on that kind of "car ads" (approx.)? Or those ads just for CPM. If so, what's the approx. CPM (maybe on PM).
Try a suttle 160x600 vertical ad to the right of the car pics with red font for 2 weeks then try blue font for 2 weeks. Delete the lower CTR.
oh after your test month, look at the two colors in comparison and the one that is lower you will delete. I have terriffic CTR but not enough traffic