A 500E? You don't happen to own your own MB, do you? Wait until Pop, used to Cadillac (i.e., GM) servicing gets his first service bill -- he's liable to sell you to pay for it. Almost all MB models (V-12 6.0 liter models excepted) incur less servicing costs than a 500E -- you'd be wise to prepare Pop in advance of purchase; and as for "power" on those north-of-S.F. hills, I'd say any V-8 S-class will satisfy him.
Good luck.