If you let me tell you which plugin is the best one for Zen cart, My answer is Google Merchant Center series, which also have Google products feed, and Google Trust Store. these three are really powerful to increasing your traffic, take my website for an example, www.uniwarestore.com , this website only have 20+ traffic, the customer are looking for the Uniware a lot, little of them looking for housewares, even discount housewares, there should be more than 100 extra traffic visit my store per day! and most of them are looking for the specific items, housewares, cookware set, kitchenware. that can make turn over rate very high, the orders will coming everyday. If you are still not clear what is Zen cart, you can