W212 is a great car, as modern cars go they are quite DIY friendly. I love mine and would buy another in a heartbeat.

I second the NA V6, and if you are interested in sedans, the m273 V8 (as in the e550). Stout and reliable engines. Motor mounts are a massive PITA and tend to go in higher miles (I had to do mine at 110k on the v8), but I suppose the v6 gives more room to work. On 4matics, keep an ear out for front CV axle noise, for some reason tends to be a common replacement on the w212. Othwrwise you are talking regular wear and maintenance items.

Air suspension does perform nicely but the maintenance is higher. Shocks will go 100-150k usually before replacement. They arent too hard a job but are expensive even with aftermarket units. Also in cold weather they tend to be rather clunky.

I recommend a icarsoft MB unit for scanning, resets and diagnostics. Gives much more than an OBD2 but without the hassle and price of a star unit. They can be had aroubd 150 bucks and stow neatly in one of the tunk side pockets.

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth