What about actual sales? As has been shown often with political surveys, people say one thing and vote another.
I'd like to see someone with more knowledge than I have set up a deal where the same search will rotate between two indentical except for template websites. Same placement of tiems, same prices, images and descriptions, just a different wrapper aorund the site.
Then measure time on the site and purchase volumes between the two. Out of the box with minimal change vs a completely redesigned shop. Equal exposure, alternating as the search engin link is clicked. Might prove interesting.....