I looked in the case I couldn't see anywhere obvious to put an internal radiator.
I'm a bit of a noob at computers etc. but I'm planning on over clocking at some point and know the stock cooler may not suffice, but I don't know if I can just add water cooling to this case or if I'll need to invest in a new case too?
With no creativity, I see that a single 120 rad can fit the rear exhaust vent. I'm thinking that with a little creativity, a 240 rad can fit the front.
If you are considering a new case and you already have the Sharkoon, I'd suggest giving case modding a try. Templates are available for standard radiator mounting, then the top (even the door) becomes a mounting option - If you mess up beyond repair, little is lost. There are videos on youtube on case modding of all kinds - my only suggestion along those lines is to have a complete plan before starting to cut on your case.