AEM compatible conductive fluid level sensor.
 

As everyone knows, AEM's fluid level sensor uses a propriety oddball thread making it near impossible to use with anything but their tank. However, it seems to be based on the VW sensor. Instead of buying questionable sensors from junkyards or getting ripped off from other vendors, you can buy the parts new for next to nothing. Here are the P/N's

Sensor 7M0919376
Gromet 7M0919382
Connector 1J0973202
--- if you buy the bare connector--
Terminal x2 N90684405
Seal 357972741B


The flat side of the connector appears to be the ground (brown) wire. I haven't verified this yet however. There are reports of anything between a 25mm (1 inch) to a 27mm (1 1/16) hole being acceptable for the sensor. Hopefully this helps as it wasn't easily searchable for me.