Thought I'd share my story so far, and update as time goes by, hopefully useful to someone else at some point.

I drive a 2011 BMW x5 (e70) with the 20" Y-spoke style 214 staggered wheels (20x10 up front, 20x11 in the rear). I live in Portland, Oregon, so you have an idea of the weather I drive in.

The OEM tire size is 275/40R20 front, 315/35R20 rear.

I wanted a good year-round tire with good snow traction (I snowboard at Mt. Hood in the winter) and otherwise a decent road handling tire for my daily commute. I like to take a corner hard now and then but I'm okay giving that up to not have to drive summer tires that only last 25k miles and lose traction in 1" of snow.

So I settled on the Continental Extreme Contact DWS tire. It's available in the staggered OEM size, but nobody had it in stock and besides I liked the slightly taller 275/45R20s that were posted on this thread. But they don't make a matching rear tire for the 11" wide wheel.

So after talking to several tire shops, including wheel tech, all of whom said the 275/45R20 would stretch onto my staggered rear wheel just fine, I bought (4) Conti DWS 275/45R20s and took my car in for the install.

They had 2 techs working at it for about half an hour, and couldn't get the rear tire to seal and inflate. And, I could see from the attempt to mount it that it was going to look really silly on the rear wheel, with the sidewalls at stupid looking angles.

So I decided to get another pair of 20x10 front wheels and mount all 4 in a non-staggered setup.

We tried the front wheels on one side to see how it would look but I thought that visually the rear wheel was too far under the fender to look good. So I decided to add a 25mm spacer.

I just purchased (2) of these replica 214 20x10s from this eBay seller who advertises that these reps are made by the same manufacturer to the same spec as BMW OEM wheels.

I also purchased (2) H&R 25mm spacers, part #50757404, from this ebay seller.

I'll get the wheels and spacers in the next few weeks, mount 'em up, and take a few pictures.

I'll try to also check back after the winter is passed and say how the Conti's are holding up.

Thanks for the others who posted the info on the forum that led me to this setup, I'm happy to be rid of the staggered rears and the limited tire choice, extra weight, and inability to rotate (call me old fashioned).

Nathan in PDX

edit: H&R, not H&K