Bit of a delayed report here, but I was able to get the Porsche service entirely by luck at LAX on a trip to SYD. I had a lengthy connection so spent a good chunk of time in the new Skyclub before heading for the shuttle over to TBIT. Outside, just before the tent for the buses, a DL agent had a phone out displaying D1/Diamond. I was both a diamond and in D1 so I inquired with him. He scanned my boarding pass and walked me over to his waiting Porsche SUV. Great guy to talk to and made the ride over to TBIT far more enjoyable than on the bus. He said they frequently will use the Porsche's specifically for the SYD flight as there isn't a ton of need for them in T2/T3 at that point in the evening.