You can import just some of the data for dev. work when you make your connection:
And there's this to help speed up working with extracts (let the server do it, not desktop):
Also, you can save extracts to your local machine. When doing dev. work you shouldn't need the latest-n-greatest extract. This way there's no download except once a week or month or whatever you schedule.
If the extracts are so huge then maybe they need trimming. There are several threads right now about working with extracts and slimming them down. Try searching for content that has Russell Christopher in it, he's an awesome resource.