If you want to change the default header layout to display a full width logo just install the following vqmod extension.
Product rich snippets is to provide users with additional information about a specific product, such as the product’s price and reviewer(s) ratings and commentary. Attract potential buyers while they are searching for items to buy on Google. Submit your product … Continued
If you want to display the weight and size (lenght/width/height) on the product details page just upload the following file to your vqmod/xml folder: Product dimensions This is the code: Change the units from line 25 to 28.
A free vQmod that removes step 3 (delivery details) on the checkout page, adapted to work with Sellegance theme. Original: http://forum.opencart.com/viewtopic.php?f=131&t=49258