XLS has 18 inchers while its spare tire is at 16.. what gives?

 

space and money my friend

 

But wouldnt the vehicle tilt to one side? sounds like you'll be mucking with suspension on the spare..

 

the important dimension is the total diameter of the wheel-tire combination, not just the diameter of the rim.
obviously, the tire on your spare 16" rim is not low profile like the one on your 18" road wheel, so the total
diameter of both should be well within an inch of each other. when i bought 17" wheels and new tires for my outlander, i just used one of the 16" oem road wheels in place of that narrow oem spare. doing that however, i had to remove the floor handle and that tool tray, but having a decent spare for highway speeds is alot more important than the convenience of holding little trinkets under the floor....

 

Ok.. I think I got confused when I saw same spare tire size across the board for LS to XLS.