Recently I've been working on The Add-On Handler again. I expect a new version to be released in a few weeks' time. Besides adding support for Superstar, it'll also have a new function: FAR Objects. That will put your downloaded objects in one FAR-file, which speeds up the loading time of The Sims (especially if you have many downloaded objects). It can still take up to 2 or 3 weeks before that version's finished though, so I hope you can be that patient. Until then, you can use The Neighborhood Handler 4.10 (not earlier!) to install Studio Town areas. Fashion skins cannot be properly installed by one of my tools yet, but as said The Add-On Handler 0.2b will be able to do that. Currently, you can download version 0.1.2b (without Superstar support) from this page (Full version), or from this page (Upgrade version).