i just ordered everything from getbmwparts and paid up the $2100. its realllllly not hard to install those items.
i got the front splitter, rear diffuser, pedals and alcantara steering wheel. With the help of a friend whose installed lips//diffusers before in previous cars i was astonished to see how easy it was, all while doing it properly of course.
just for comparison my shop told me $60 for install for each lip/diffuser so $120. not bad even if i decided to do that.
My X5 M sport is a lease. i didn't care tho i liked the parts, and got everything on the car asap so i could just enjoy it. Only thing i did pay my performance shop to do is the H&R sport springs and full X5M carbon/alcantara interior trim
cheers and goodluck !