I've been window shopping W221s. It's high on my list of desirable cars. If I get one, most likely to be an S550 4MATIC. I have a few questions though:

1. How bad are they for DIY? I've read they're better than Audi and BMW. Don't have to pull the engine to change the starter or anything like that?

2. I think I want 4MATIC. Car won't be driven in snow or salty roads if I can help it, except in an emergency if my truck has problems (which could happen). I mainly want 4MATIC because I've read it is equally as quick in 0-60 as the RWD version. I like the idea of a car that I can hit the gas and it just goes without any tire spin, loss of traction, or need for torque management. Is that what 4MATIC is like? I have no interest in doing donuts or smokey burnouts.

3. What are all the changes and options in the USA models between model years? Mainly interested in 07-10. I'd be interested to know all changes, minor and major. I already know 10 was a refresh year, but what are the changes in 10 that I can't see?

4. When it comes to buying a used car, I know beggars can't be choosers, but I'd still like to try to get as many toys as possible. How would I identify if a car has specific options? For example:
A. Ventilated seats = Perforated leather.
B. Distronic = Center part of grille has solid black plastic in openings.
C. Night vision = Button with icon of road and moon next to headlight switch.
D. Headlight washers = Button with headlight washer icon next to headlight switch.
E. Park assist = Sensors on bumpers.

Anything else? Also, I noticed some cars appear to have the headlight washer doors on the bumper, but no button. Did it get moved, or do cars lacking the button just have blank filler panels instead of real washers?

I'm sure there are also features/options that can't be ID'd in photos like double-pane windows, is there a place I can run a VIN and get an accurate list of options for a specific car?

5. Generally, should I avoid 07? I've read about transmission issues and balance shaft problems. Do I avoid most problems by going to 08?

 

I would say you want a 10+. A little fresher cosmetically and a lot of the more popular features from the prior years got consolidated as standard:

Active seats with massage. (All W221's got heated and cooled seats and perf leather)
Back-Up Camera
Parktronic
Paddle shifters
Aluminum pedals
Three color selectable LED ambient lighting
Ipod integration, HD music storage

Common options were Pano roof, nightview assist, distronic, active parktronic. I believe the headlamp washers in the 10 and up don't get a button. They cycle on after the windshield washers run ten times.

Personally if I didn't need the 4 matic for inclement weather I'd skip the added weight and complexity for a RWD car. More options in terms of aftermarket wheel set ups as well. Neither car is a screamer off the line with or without the ESP.

I don't think the S is remotely easy to work on but I'm not a mechanic. Of course no post of mine would be complete without recommending a CPO car and as much extended CPO as you can swing. An S can bite you very hard on repairs.

 

If you get access to StarTEKInfo (the official Mercedes-Benz USA, LLC site for hosting service and repair technical documentation for Mercedes-Benz vehicles. http://www.startekinfo.com/StarTek/ - costs money to access, has multiple plans, you need to learn how to find what you are looking for), or purchase a local version of EPC/WIS/ASRA and there are several available on ebay

http://www.ebay.com/sch/i.html?_from...2Fepc&_sacat=0

you can also ask a question on this and other forums and others who have access to this information will sometimes provide you with the appropriate information.

Working on the cars yourself is not bad at all provided you have access to the appropriate procedures detailed by MB, have/purchase any special tools that are required and of course some experience working on cars in general. At least with this information you can review the procedures for repairs/replacements to see if you want to take the plunge on DiY repairs for a particular problem.