I would recommend the same KWv1 setup for the xi.
'08 Sparkling Graph. E92 335xi (ZSP w/ 18s | Saddle Br. | Grey Poplar) (Returned)
'11 Space Grey E92 335xi M-Sport (KWv1 Coils | Saddle Brown | Bamboo) (Returned)
'14 Mineral Grey F32 335i M-Sport (Dinan DHP | LED Lights | Coral Red | Hexagonal Aluminum)