I spent the money on BroFab E30 front hubs and rear MiataHubs, they were something I was absolutely willing to spend the money on because stock Miata hubs are time bombs on track, especially with aero/big tires. The cheaper alternative to the MiataHubs is BroFab machined BMW E30 front hubs/wheel bearings and BroFab rear machined Toyota Yaris hubs pressed into stock wheel bearings. Doing either of these options doesn't require changing brake/rotor setups since the 4x100 pattern is retained, so the cost is just the hubs and bearings.

The fact that the stock Miata hubs and front bearings suck and the number of people seriously tracking Miatas means they've got a good market size since it is very much a safety thing at minimum.

For the BRZ it seems the advantage is wheel choice and that is about it, for track people being that 5x114.3 wheels in 18x10 or 17x10 with the right offset are available and relatively cheap.

Requiring a different knuckle would preclude a fair number of track people from the market due to most rulesets requiring stock knuckles/uprights.

I guess the best route here would be to figure out how to buy the front bearing without a hub pressed in (or machine some other existing stock hub that would work) and machine some existing stock hub to fit into the front bearing otherwise you've got an expensive product with a small market.

Karcepts is an example of CNC'd hubs that press into a stock wheel bearing and BroFab sells the machined Yaris hubs, as pricing data points.