1| If you want to expand an AIO/closed loop, you're going to tear open the entire unit and in the process void your warranty. Yes you can expand upon it but since the radiator is made of aluminium and the cooling plate is made of aluminium, you're going to face issues with galvanic corrosion if using distilled water. Corsair use a proprietary coolant to minimize/reduce/somewhat eliminate the corrosion process but they weren't designed to live in your system past it's warranty period anyway.
2| On top of that you're also going to have to deal with the weak pump that is only capable of driving it's own system as is. Expanding on it would mean sourcing a better pump.
You may want to read through the watercooling sticky(located in my sig space) to get a better understanding of what 'm saying since opening up a closed loop cooler effectively equates to you building a custom level watercooling loop albeit the former would only require more resources as opposed to building a custom loop from scratch.
In short, don't bother.