c# + Webbrowser + Proxy + Javascript

I need a Solution, a component that i can add to my .Net project, which must be able to Do the following 1. A Web Browser 2. Set proxies on Instance Bases (i will be running on multi threaded, each browser instance should have seperate proxy setting) 3. Should Interpret Javascript 4. Allow To Edit Headers/GET/POST Data Before any Request is sent to any Server 5. Allow a DOM Like Structure to Access Web Documents different Elements (getelementbyID, getelementbyname etc). If you think you can Make a Component Like this, Send in PM with your Rough Solution (not component itself) about how are you going to achieve the points i have mentioned, and on what base you will be making them (gecko, webkit, mono ?? )