Fixing Earth To ECU

Afternoon,

I'm looking at running a new earth to the ECUADOR from battery negative, where on/around the ECU is the best place to attach it ? I can't see any earth wire/strap on ECU at present, the only earth in the box under drivers seat is a small black wire bolted to the floor of under seat box.

ECUADOR - would need a long wire !! Meant to read ECU !!

Bottom of the tray there are 2 studs for earthing to. Although I ran mine to the bolt that secures the ECU

The ecu does not rely on an earth connection through its case - stick it in a plastic box if you want.