I can't see why a low corner would be a failure if the tester couldn't find an actual fault. Mine had oil misting so it was obvious, although it didn't leak air! Also worth mentioning that detaching the air line is easier on the rears as you have more access. Another thing probably worth a mention is the pre and facelift models share the same struts if you're looking to buy used. There's nothing complicated about removing/refitting the suspension system on the LS430, apart from limited access on the front airlines.