look closely at the option packages on the E350. to get a "decent" car, you'll need to get the P2 package just to get xenons. leather is optional, and most cars come to the states unless custom ordered with MB Tex vinyl.
there is no comparison in materials and build quality between the F10 and the E350. i've had two W212 E350's. if you want a sea of plastic, get the MB. you should be able to get invoice + some bucks for the dealer. i can't think that dealer's aren't willing to come down. the economy ain't that great.