Steering is light on ML - but would not suggest dangerous unless you are pushing what's basically a truck at dangerous speeds often ...

We liked the ML but the one thing that put us off was how much it leaned into corners ..even with airmatic suspension ...

In the end we went with the X5 hands down ... it just a much better SUV proposition IMHO.

One thing about X5 ride - the bigger the wheels the harsher the ride (but there is some handing improvements also) ..its really about what you want.

There's no doubt that 20's (and up) LOOK fantastic (wider, meatier, arguably points for status/posing etc) ...BUT ..ride comfort is traded off for 'sportier' handling ...so if you're wife is thrashing around at high speed and is OK feeling more lumps and bumps then 20's are good.

Personally we stuck with the 18's as standard ..they look fine, best ride comfort, and you're not mucking around with fitting chains in winter etc if you need to. You'll also save $$ that could be put into things like comfort seats to help absorb more shock from your bum etc ....

good luck with your decision purchase either way ....