A few things I do know about below:
1. any known issues with the model?
Cant comment on this as I have not used one
Did fine this: http://www.honestjohn.co.uk/carbycar/index.htm?md=627
2. are there any recurring costs other than the things involved during a normal servicing? Any parts wearing off quickly?
3. when was the facelift model launched? What are the major differences in that model?
Face lift was launched in 2006.
The facelift version come with few exterior alterations – look for the fresh front bumper, more pronounced V-grille, deeper side skirts and active headlamps. Most changes are under the skin, including revised engines, improved safety kit and an end to brake-by-wire.
4. what options come in the ‘avant grade’? what are the other grades/categories?
The Avant Garde is the top spec model with all the extras like leather etc. The grades are Classic , Elegance and Avant Garde
5. what is this technology called ‘kompressor’?
The Kompressor is the Supercharged/Tubocharged engine units.
6. how eassy will it be to re-sell the car?
The car should hold its value well. In SL mercs hold their value very well cos of the 'Benz' name but not sure about how easy it would be to sell as these things do cost quite a bit so I guess the potential buyer market is small.
last but not least how much will a brand new 2003 fully loaded model cost?
No idea about this but I saw a W210 sometime back on AL for about 8mil so this would be around 12-16 mil range?