Jim - I have one of these.

I may be wrong, so don't quote me on this, but I think you can use the kit to send info to two devices - ie the guage and your ECU.

This bit in the ad on ebay (if I'm reading correctly) seems to back this up:

It features the same industry-leading patented digital circuit found in the proven LM-1, and includes digital in & out, plus two programmable analogue outputs. The LC-1 can connect directly to the XD-1 for a standalone AFR gauge, and is ideal for using with an ECU

I don't think you need to 'spit' the signal so to speak - I think you can use one of those outputs or the digital out.

Of course I'm prob hopelessly wrong , but that's how I think it works.

Simon