Wow has this already happened? Technicians that have taken the M3 training course are the only ones to work on them and should know that DCT units can only take a certain fluid.
The list price for a new DCT transmission is around $10,000 plus labor.
Also, not sure if anyone knows about this but the wet clutch unit is not sold separately. You have to buy a whole transmission which comes with it. It's not like a clutch kit you can buy like on an E46 M3 SMG or non DCT transmission.
Hope you guys have a plan to extend the warranty if it fails.