free document sharing website w/ bandwidth control

I need help completely rewriting the code for a website that shares electronics documents and manuals. the code creates directory indexes, handles the file downloads, and limits bandwidth per visitor. the code will also be released as part of an open source project. ## Deliverables I have a working site already, that has been running for over 2 years. I need some help rewriting the code to update it and fix known problems. the project is small, but not very simple. it needs to index files available for download, manage the download transfers, and track bandwidth usage. the site gets over 1000 visitors a day and is on a shared server, so performance is an issue, and must be carefully handled.