I think spacers are great, I run them on all of my cars with stock wheels.
This is the one I’m using, they are super lightweight:
https://www.oemplusdesigns.com/products/lightweight-wheel-spacers-toyota-gr-supra-a90-91
With stock tires 15mm front and 18mm rear is perfect, but now I switched...
Our ground effects kit (front lip, side skirts, rear diffuser extensions) is pretty affordable. The pieces are also available individually though and they don’t require any drilling.
https://oemplusmods.com/products/extensions-body-kit-toyota-gr-supra-a90-91