For JimF... hi. Long time no talk. Hope all is well on the left coast.
For michiganbenz ... glad you found ALLDATA useful. I've had my C pillar trims and back seats out... not a hard job at all. To take all that out, all you need is something to pry with (I used a large screwdriver) and a 10mm socket. Go for it.
For jkmmrs... haven't changed cats on my car, but it looks pretty straightforward once you cut the muffler off (Ouch). Bet they're expensive. Wouldn't change unless you believe the cats to be bad internally. My S500 Coupe cats look like stainless steel to me.
Haven't changed the charcoal filter, but STAR magazine ran an entire article on changing it recently... lots of stuff to remove, but very straightforward and you can do it all under the hood. Trickiest parts are taking out the wiper assembly and then having to use a vacuum pump to retract the seal.
For royaiii... couldn't disagree more. The W140 (at least so far) hasn't been bad to work on at all. Its well laid out although very complex. It is certainly not limited to simple maintenance repairs. I can't imagine owning a car I don't work on. I've owned several American cars that are much harder to work on and, frankly, aren't designed to be repaired. My experience with my W140 shows me that most stuff is made to be repaired instead of just being thrown away and replaced.