What is the service life of early ML320's

With regular maintenance, how many miles can you expect from these trucks?

A couple of dealers (salesmen) have told me they are "good for at least 300,000 miles", but that seems questionable with the troubles posted on this and other sites.

I usually run cars to pretty high mileage before giving up on them and I realize high mileage vehicles need repairs along the way. I currently have a '69 Lotus with 143,000 miles (approaching a record for Lotus), an '88 Chevy van with 215,000 miles, etc. I'm familiar with the usual stuff needed to keep older cars going.

I'm wondering about the expected life of major components. Is it reasonable to buy a '98 or '99 ML320 with 80 to 90,000 miles on it and expect to go another 50 to 75,000 without major engine and drivetrain trouble?