Product Option Values Import Recommendation

Wasn't sure where to put this..

I have about 20,000 products
I have many products that have 5+ options per product
My total option values for all products are about 2000 different option values (red/blue/medium/30mm/black/low black/high matte black...)
My total options are about 10 different categories (size/color/height/mm/gauge...)
Most of my suppliers have product values listed in Excel as so:
SKU Model # Name Option Option Value
All product options have own model #s and their own SKUs.

What is the best free or commercial Open Cart extension to import these option values and assign them in bulk?
I don't care if I have to tweak or edit the product Excel file, as long as I don't have to manually assign every option value in Open Cart. As they are assigned in Excel, there must be a way (program) to import them and assign them from that file.

I am asking for opinions or recommendations so that I don't go through more trial and error and spend more money on products that don't work good with bulk option values.

Thanks for all help and input! I will really appreciate it.

Excel / CSV import/export extension should be able to do what you need.