Shopping Cart recommendations?

Hi folks, I'm looking for personal recommendations on shopping carts and ecommerce solutions. I'd like to be able to change the code as much as I need, so I'm wondering whether one of the Perl Open Source ecommerce projects are good news? These are the features required: -The shopping cart system itself with the usual product info, customer registration, and database (I think a real, relational database would be preferable over a flat file database. There'll be about 500 items) - Purchase by either credit card or customer account. (Actual payment processing will be manual) - Customers can write their own reviews (this is for a bookseller) - Feedback/Customer Service correspondence. (I can of course easily write my own add-on, but it would be nice if it were included) - A system which uses templates would be good, so we can seperate the design from the code. Are there any useful features you know about which I haven't mentioned? Thanks for any suggestions!