Date registered: May 2016
Vehicle: 2000 S430, 2003 S430, 2003 S600 TT, and 2005 E320 CDI
Mentioned: 169 Post(s)
Quoted: 962 Post(s)
As 260e_cruiser points out, sure, they'll fit, as long as the ET and bolt pattern are correct for the car. You will need lower-profile tires, though, to maintain the proper outer diameter.
As for lowering it, I also have a 2005 E320 CDI. Great car; I drove it to work today. It's a good overall height, and you may find that the car with those 18" wheels looks just fine without lowering it. My car has the 16" factory wheels, and I think it looks great with 'em.
2000 S430 (Dad's car, used for special occasions)
2000 S500 (wife's DD: my first W220 project car)
2003 S600 ("sex on wheels"--second w220 project car)
2003 S430 (one of two current DD's--third W220 project car)
2005 E320 CDI (the other current DD--first W211 project car)