100K?!?!? That's nothing! Your Benz is still a baby. Keep up that regular maintenance and I'm sure you'll hit 500K with minimal work needed. I have a 300K M103 block I'm using for my turbo project and all of my original components such as cam, rockers, head, block, rods and crank are in basically perfect condition. My engine builder freaked when I told him how many miles were on these components. In fact, the engine ran great before I pulled it apart. Mercedes makes a great product!
Adam

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Current Stable:
01 ML55 AMG
92 500E (a few mods)
87 300E (lots of mods)
00 Chevy 3500HD Diesel Box Truck
68 18' Donzi Marine
06 GT i-Drive7 1.0 Mountain Bike (with GPS!)

PREVIOUSLY OWNED:83 300SD, 87 420SEL, 88 420SEL, 90 420SEL, 86 560SEL, 86 190E 2.3-16V AMG, 94 E320