We designed and integrated our product database, inventory tracking etc... with our website and don't wish to use any product database features...

Here's what we are wanting, does nopCommerce fit?

From our products screen, ability to pass:

product code
description
price
quantity and extended price

to a shopping cart and have the cart manage the sale, processing, user profile, previous sales, etc...

Our data and products must stay in our existing database and product control structure. We simply want a shopping cart and order tracking that works with our website rather than running our website...

Would this be a good fit?