Update report - put about 600 miles on the tires and the high speed whine/drone is starting to go away. Much quieter than it was right after install. As for ride, it does feel less firm during turns and aggressive driving but the quiet is worth it and the tires also soften road transitions and expansion joint slaps. Well worth the switch for me but i wish the RFTs weren't so noisy.
Current: 2010 X5M
Former BMWs: 2009 X35d, 2008 X5 4.8i, 2007 335xi