Just posting the instructions/details again:

Go to:
http://www.filter1.com/
Click on ”Online Ordering and Quote System!”
Click on “Online Ordering & Quote System” (again) (or you can go here directly https://order.filter1.com/)
Click on the “Click Here” button for “If you are already a Filter1 customer”
Enter “moparts” for the Customer Number
Enter “moparts” for the Password (Both are case sensitive so use lower case for both)
Click on “Login”
Click on “To go to the Quick Order Form, CLICK HERE.”
Enter the WIX part number and quantity
If you aren’t sure about the part numbers there is a “WIX Catalog” link above