Yeah I've been considering this package from tirerack as well.
BMW is selling their cheapest 17" package for about 2223.. I priced out the tire rack one at about $1700 not including duty. This includes the TPMS sensors (did you get tpms installed for yours? If so, you used an 09 528 as the reference and they work? I was thinking I'd have to try a 2011 model as I believe BMW changed TPMS sensors mid 2010)
Anyhow probably looking at about a $400 difference.. BMW is offering free storage of the summer wheels ("$200 value".. uh huh) so it does narrow the gap a bit.
I would love to see photos of these wheels on an X1 as I must admit I'm not confident on how they're going to look which has given me pause to pulling the trigger, but of the offerings I've seen on TireRack for wheels, other than OZ's (2-3 times the price) I'm not sure anything else appeals to me either.