Having tried virtually ever Belt manufacture in the world. I have found Safecraft to be the best Driver restraint system on the market. Yes, they are expensive with current SCCA rules allowing five years of service, they are less than $100.00 per year.
The Safecraft cam lock buckle design is unique, in that the buckle tang also acts as the adjuster. This design keeps the adjuster nearer to the center line of body, rather than around your hips. Making getting the lab belts tight much easier.
The shoulder belt adjusters are machined, rather then cast, for ease of adjustment.
Our typical Spec Miata kit features clip in lap belts, wrap around shoulder belts and universal sub belts (either clip in or bolt in tangs can be added)
We stock 2" lab belts with 2" hans style shoulder belts in black. Other designs and colors are available. Special orders take about ten days from the time we order to get from Safecraft Chicago facility.