this engine does not suffer from OSV like the older m62 and m54. although the diagphram does tear, but will set the MIL.

So after 30 seconds from cold start, the valve lift is transitioning from 6mm, to 0.3mm, this causes uneven cylinder filling which results in rough idleing. the correction is to replace the eccentric shafts and all 16 intermediate levers. to find out the correct levers to order, you must removed both valve covers and inspect the stamping. if you are out of warranty, you can ask bmw for assistance, in which they will cover the repair 100% parts depending on your relationship with them. although not recommended for x5's you can increase the lift from 0.3mm to 0.8mm through service function from BMW, this will improve the idleing characteristics.