I'm looking at the 18" Bridgestone runflats.
http://www.tirerack.com/tires/tires.jsp ... &tab=Sizes
At 23,000 miles, I'm expecting to replace my factory tires in about six months or so. 30,000 miles from stock tires isn't too shabby.
I hate aftermarket wheels, but the OZ Ultraleggera are 9 lbs lighter than the Ford Racing 18x8's.
That's a huge difference in unsprung weight, and should easily offset any range loss from not using an LRR tire.
Also, the Bridgestone has a slightly higher load rating than stock, which should also help with rolling resistance.