Budget WBO2 wideband controller roundup

I wanted some wideband o2 in the car. Partly because almost all EFI controllers will still rely on a separate wbo2 controller. Partly just to have a gauge which I can keep an eye on. I prepared a small comparison about the controllers I've found.

The head #2

After some busy weeks, it seems I never catch up with myself about the engine project. It is indeed running fine for some time already. But, back to the head now...