Can anyone confirm two things for me?

1) If I remove the oil pressure sending unit (alias: oil pressure sensor, oil sending unit, oil pressure unit)... is a bunch of oil going to come pouring out? Can I depressurize the system simply by taking the cap off?

2) Is the oil pressure sending unit a 1 wire system? All of the pictures I have come across from various repair manuals seem to show a plug with a big loom on it.. as if to say its beefier than one wire.

 

Yes, it's single wire to plug. You'll need to remove the oil filter to get to it anyway, so the bit of oil that drains is all you need to remove. You don't need to drain the entire engine and oil is not under pressure with engine off. It's all gravity at that point and the sender sits higher than the oil pan..