Ecommerce plugin

My store sells computers online. Basically there are about 15-20 products and the customer can change the final outcome(like choose OS, processor, RAM).

I have tested WooCommerce so far and it is great but the issue is that adding custom variables to products can get extremely tedious once I have more variables the few, and considering that I will have a minimum of 4 variables with each product, it is a deal-breaker to me.(If anyone knows how to get around it then I would love to hear it).

Other requirements that I have are:
– Easy and flexible themeing.

I do not mind if the plug in is premium. I just want to find something fast that works.

Thank you all!