If you're not actually using a STORE on your website, and not cataloguing any actual PRODUCTS then you don't need Zen Cart.
So ... why not use Mailchimp instead?
Simply set up a campaign, add specific fields for the questions you want them to answer, and then when they submit the form they'll also be added to your mailing list.
Then you can use their answers in the mailchimp database to give them specific feedback on the products they're interested in. Plus they will have opted-in to your newsletter mailing list, so you can email everyone monthly with special updates related to your business.
Or you could use another service like wufoo.com to put up a contact page where you add custom forms, for same purpose as I suggested above. The difference is they won't be opting in to a newsletter, so you won't have permission to "email everyone on your database" that way. But you will get specific emails from each customer who fills out your form.
Or, if you do decide to use Zen Cart, USE A MODERN VERSION. Don't use v1.3.8 like you said you're using when you started posting this discussion. That version from 2007 has security holes that were fixed SEVEN YEARS AGO! There's no good reason not to use the latest version of Zen Cart.
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