Why not use this much simpler circuit?
https://www.onsemi.com/pub/Collateral/FIN1028-D.PDF(It's just a receiver. I'm not going to draw that up.
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LVDS receivers are normally spec'd for 100mV, but typical performance is a comparator with <10mV offset. Or, just use a comparator; or best yet, a comparator with adjustable offset, if you can find one (or use an op-amp that does, that is also fast enough to be usable as a comparator at this clock rate?).
Unfortunately, adding an offset to a bus is surprisingly difficult -- the above example works for one-offs, but it's not scalable because it puts a current offset into the bus itself. A source and sink around the offset resistor would fix that in the average case, but would leave a worst-case residual offset.
The other difficulty is EMC. The previously stated 5V common mode range is ridiculous for an automotive environment (perhaps why this bus didn't last long?). Heavy common mode filtering at least will be necessary. Exceeding the CM range activates ESD clamp diodes, stomping out bits. An isolated receiver
might be okay (has to be done carefully to avoid loading the bus with capacitance), but this is a somewhat heroic level of effort and maybe it's not necessary, I don't know.
Or maybe a completely different tack is acceptable -- have I read this correctly, that it's a high clock frequency ("6MHz") modulated at a much lower symbol rate? Just AC-couple it, read it out from a transformer! Eliminates the oddball offset, eliminates common mode and isolation problems, lets you do whatever you need locally to process the signal, and commodity transformers may be suitable (think Ethernet 10/100, or ISDN transformers if you can still find 'em). Downside, this puts a fair amount of impedance on the bus, so again, it's not scalable.
Tim