Is there a script to open the greasemonkey 'Mange User Scripts' window maximized, basicly if you have loads of scripts you have to scroll. Is there a script that resizes the window depending on the amount of scripts you have?

I don't think a greasemonkey script is capable of resizing the Manage User Scripts window because there is no page loaded for that, it's a browser extension. That said,
1. Try re-sizing the window manually.
2. Use a case statement on the window.location to combine several small scripts into one for easier scrolling

-Joel