The following shops are maintained by others in the Speeduino community. WTMtronics LC has no involvement in their business dealings, but I do communicate with all of them, and they are great places to get Speeduino stuff.
Speeduino (Australia) — https://speeduino.com/shop
DIY-EFI (United Kingdom) — https://diy-efi.co.uk/
SpeedyEFI (US, Washington) — https://speedyefi.com/
Proyect ECU (Mexico) — http://proyectecu.com/