Interspre Shopping Cart Modification

I am looking for someone who can modify our existing shoppingcart to our need. Currently we are using Interspire Shoppingcart. We want to add a section where the customer can customize their order. I need to modify the cart to be like Dell.com. Custom options allowing the customer to choose many different optional add-ons per item. Like adding ram, software, etc... Please msg me with your questions and provide previous examples.