Nice to do some work that doesn't require lying under the car for a change.
The steering wheel is a cheap Momo lookalike bought from eBay for $40 including a hub.
I think the diameter is 320mm which is considerable smaller then the standard wheel.
The main reason for the swap is to get more room for the knees as the standard wheel makes left foot braking difficult.
The smaller diameter also gives a bit more feel and sharper steering.

The fitment was easy once I understood that I had to rip off the contact plate that came with the hub.
I guess it's used for the 1.6 NA or cars that came without an airbag.

Looks ok. The horn works and everything..
I read on forum.miata.net that one could disconect a couple of blue boxes located behind the steering rack to get rid of the annoying airbag warning light that started to blink after removed it.
I could not find any of the boxes on my MX-5 so I guess they have a different location on european cars.
It should also be possible fix the light by using a 3.3 ohm resistor between the two wires going to the airbag.
But where can I buy such a resistor ?