I am currently studying German because I would like to study my bachelor's degree at ETH Zürich. To be admitted I need to either get at least an 80% grade in all Goethe C1 modules or at least a 60% grade in all Goethe C2 modules (I only need to pass the exam). I'm currently at a C1 level (but I don't have a certificate to prove it) and I've got approximately 4 months to prepare for the C2 level (2 months for the C1).
In my opinion trying to get at least an 80% mark in all 4 modules is too high a risk (I still make grammar mistakes - I've only been studying German for 3 years) and that's why I'm considering taking the Goethe C2. I would be extremely disappointed if I had to repeat the exams (they are extremely expensive and I've only got one year left before doing my bachelor's). From your own experience, is something like this feasible? Which learning resources could particularly benefit someone in my situation (ignoring the fact you don't know my own strengths and weaknesses)? And to make matters worse, I've only got 1-2 hours daily to spare.
I'm pretty new to this forum so I hope I'm not breaking any rules on what you can ask :)
EDIT:
Source: Sprachanforderungen (ETH Zürich)