This one?
It slides into the metal of the ECU cage, remember to bend the very top of it under/behind the A pillar trim first. Then finagle it under the rubber strip that runs along the door jam, at the same time pushing it sideways into a green clip.
The under dash trim slides into a trim clip as depicted by my excellent drawing. There's a white plastic thing that it slides into on the heater/clutch pedal side too.
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MY97 940 CD LPT Super Sports Edition 2 Turbo, Midnight Purple, 175,000 miles.