We have 400,000 products with many different attributes and categories that need to be imported into Magento. We need someone to import all of these into the store. Please only experts in Magento apply. Preserving the data is very crucial to the import process there can be no mistakes. Each product has 1 image.The products and attributes are in database format. We are not sure if we should be creating multiple attribute sets or just use one. There is a total of 9000 unique attributes. I also have a custom built product and attribute importer script that can handle 25,000 at once. The issue is putting it into a format the importer can understand.