What

I have an existing site, what I'd really prefer is some sort of sync / upload changes process, but failing that I should be able to import a site or its backup.

Why

I wish to try local development. It is not so useful unless I can work on a full copy of my site. Ideally everything would be the same including plugins.

How

A sync or import function, probably some way to specify what you want the import to take. If sync some way to specify what gets synced (probably don't want everything).