Silent installer for Chrome and Firefox browser extensions

We need an installer created for a browser extension, both for Chrome and Firefox. The browser MUST NOT ask the user to enable the extension manually after the installer runs, it should all work without user intervention (so the extensions will need to be added directly into the "database" of the browser). I have the logic already done, and it will be explained to the chosen bidder so all you need to do is to implement it in C++ (without any external dependencies, and it must work on Windows XP, Vista, 7 and 8, also keep the executable as small as possible). Also include the phrase "wall of text" in your bid description if you're actually reading this. The installer will have to download some files off a remote server (including the actual extension files), be able to parse and modify JSON (for Chrome), modify SQLite databases (for Firefox) and do some string and file manipulation. I am looking for clean and understandable code (you don't need to have comments everywhere, I'm a programmer myself). I will provide additional details to potential bidders. I'm looking to have this done in 24 hours after choosing the winner at most, so make sure you're available before posting. I'm looking forward to receiving your bids.