The only reason BMW does not recommend rotation is that due to " free " maintenance
schedules every 15k would mean an additional service at 7500 k, I waited until 16k to rotate my tires due to slight tire cupping on the front tires, I feel no adverse effects from this at all and plan to rotate every 7500k when these current tires are replaced. Also another profit item for dealerships ( tires ) .
2003 3.0 X5 ( E53 )
2002 330 Xi ( E46 )