E70 Winter Wheel suggestion?

[macming]

I just picked up a 2011 X5 35i and am looking for a winter setup. The X5 came with 255/55/19s (correction 255/50/19) right now, as I'm looking to downsize to 18" wheels, what tire size should I consider (correction 255/55/18)? I'll probably pick up a set of Blizzarks or Michelin X ice.

From the bit of research I've done, I think the E70 uses rim mounted TPMS sensors, so I'll need those installed. Does the center bore size change between generations (74.1mm for E70, and 72.5mm for E53)? I'll probably get a set of OEM rims used and go that route.

I guess my question is, what generation rims should I look for [E70]?

Thanks,

Ming



I found some info on TPMS sensors:

For 2011 X5's built during 8/10 or 9/10, the older sensor is required.
For 2011 X5's built during 10/10, we will need to run their VIN number.
For 2011 X5's built during 11/10 and later, the newer sensor is required.

The old part number was 36236781847 and the new one is 36106790054