The balance shaft issue extended a ways into the 2007 model year also. My dad's is a 2007 and it had the problem.

SBC is covered by warranty for now.....but eventually it can become a good sized expense once thats gone, but not unreasonable.

Airmatic is nice, in my opinion worth the cost to keep it going properly.

C320 wagons are awesome unless you live where there's ANY salt. Someone around the corner from me has a C320 wagon and its rusting to pieces. The 2004+ ones were much better in terms of corrosion protection but they fitted the anemic 2.6 liter M112 to those, so they're pretty gutless especially with 4matic....which most were....and the MPG is astonishingly bad. My enormous Metris van averages 23.5mpg city, the C240 wagon got about 18.5....and was 1,400 lbs lighter....

S203/W203 Still remains one of my favorite MB platforms though. Solid and fun to drive.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)