The "C" with disc brakes is the last and thus the most "developed" 356. From 1955 to 1965 there were four major enhancements to the 356 chassis (T-1, T-2, T-5 and T-6) which make the steering and handling vastly improved.
I have owned my Cabriolet since 1979 and have found it to be a fun and reliable car to drive. If you want to buy one of these, you must know where they rust and learn how to spot correct and incorrect rust repairs. They all rust! Properly repaired rust will not be an issue unless the car is abused by being driven on wet/salty roads.