I have a 96’ with a single turbo setup. Do I need to run some sort of breather on the driver side valve cover port or can I Y both valve cover ports to an inlet of a catch can and run the outlet of the catch can to the intake?

 

You could do either. There are some good threads on this site dealing with this.

if your car is turbo charged, the existing ports may not work as intended, and you may wish to route your ‘intake’ connection to the intake post filter but pre turbo, and cap the stock intake port.

 

It is a lot to read through, but all your answers and alternatives are in here: https://www.miataturbo.net/engine-pe...-thread-99549/
Is your turbo car for the street, or a race car?
If a street car, you can probably do what you are asking about.
On track, it will most likely dump too much oil into the intake manifold.
I use vent to atmosphere and plumbed the return back to the sump, so as to not run out of oil mid race. But on the street, or with occasional track days that is typically not required.

 

You don’t need a separate breather for the driver’s side. You can Y both valve cover ports into a single catch can and run the outlet back to the intake. Just make sure the catch can is properly sized and the hoses are routed to avoid kinks or heat exposure.