[hotpotamus]

I don't understand the legal requirement thing. In my state, I'm pretty sure I could put a straight pipe down there and I'd never have an issue. In fact, I'd probably look into it if it happened to me. That said, I know my state is pretty lax about that sort of thing. Curious how it's actually enforced in others.

[sokoloff]

You might need to install a downstream O2 sensor simulator to prevent an OBD2 failure to verify function of the (now missing) converter, but those are readily available for off-road use as I’m sure would be your application. ;)

[hotpotamus]

Yeah, the cheater plugs are part of the deal. I'm pretty sure they're just fixed resistors so it's not complicated.

[sokoloff]

Usually a fixed resistor to simulate the heater and a square wave oscillator to simulate the O2 sensor output cycling between lean and rich.