If you're not used to big cars, it can be a handful, esp when backing up. I've always had cars with long wheelbases, so the SEL is small to me
My wife uses it primarily for work, all city driving and loves it. Safe as a tank!
If well maintained, it should last hundreds of thousands of miles. Makes sure you have records with the car. Have a good MB tech check the car over.
A/C repair can be costly, the most expensive part about the rear end on the 56SEL are the rear shocks (about $1000/pr
) other than that, it's not a big deal-- spheres are cheap and can be done yourself.
I've found cost of ownership to be low, as I can do some work myself, but will leave the timing chain and guide rails to a tech (due soon).
Engine-wise, at 160k miles, I would hope the the chain/rails have been done and maybe new valve guide seals.