What possible consequences of connecting speed/reference sensors to wrong connectors?
 

Just had to replace the sensors and can't figure out which goes to which connector, connectors on wiring harness not marked. Was wondering if I could just plug them in, try starting the car and see which one works without major consequence. Trying to avoid tracing the wires back to the dme and having to pull the dme to see which is which, seems like a pain.

Yes, you can swap them without damage.
Of course they have to be correctly connected for the engine to run, but that's what you're trying to do!

Thanks! Didn't wanna try it and find out I wrecked the dme or something by hooking it up to the wrong connectors.