Is there any performance difference in 80 pin compared to 68 pin or are those 12 extra pins just there for stability when hot swapping drives?
No, there is no performance difference. The interface is the same. U160 80pin and U160 68 pin are the same thing, different connector.
80 pin is called "SCA" which stands for single connector (or contact, or connection) attachment. It is designed for simplicity for hotswap in servers, but there is nothing wrong with using it in a workstation with a 68 pin to 80 pin adapter.