Im not sure who came up with "Lexus recommends". According to my manual it's a requirement not a recommendation. Also, people that say "I've been putting 87 on my LX for over 100k miles and haven't had any problems." Sure you haven't had any problems because that's why knock sensors are there for, but this doesn't mean that your engine is running at peak performance or is in top shape. Engines loose power over time but those engines running on 87 have most likely lost more power from the increased knock events, specially with how conservative Lexus tunes their engines.

<-- MFer still ain't alive!