Most of the Ward's staff would swear the Mercedes-Benz ML320 is getting stronger and more spry as it ages (okay, so it's only nine months old). The amount of mid-range torque ground out by the 3.2L SOHC V-6 still surprises with every punch of the pedal, as evidenced by the beaming, up-to-no-good grins that return the keys to their little hook on the wall.

Sitting down to crunch the numbers accrued by our long-term M-Class since the last update also produced some pleasant surprises. After 29,200 miles (47,000 km) of hard driving, 11,793 miles (18,978 km) of which we piled on in the last three months alone, our hardy Teutonic friend guzzles less fuel than ever. It has averaged 19.3 mpg (12.2L/100 km) over the past nine months, jumping a full 1.1 mpg since last we checked. Not half bad for a vehicle of its heft. All that torque, with decent fuel economy to boot, speaks volumes of the manifold capabilities of Mercedes' first-ever V-6 engine - with a 3-valve-per-cylinder layout to boot.

So when the excellent Flexible Service System says it's time we service, we listen. The FSS does a great job of "maximizing" intervals between maintenance - in effect, there is no service schedule; FSS evaluates a variety of driving parameters and sets service accordingly, so you're not locked in to service at, say, every 5,000 miles when you just don't really need it.

Thus it wasn't until just over 23,000 miles (37,000 km) that FSS called for the ML320's second scheduled checkup. Try as we might to understand how the dealer gets $244.61 out of a routine maintenance stop (read: oil change, new air filter and wipers), at least there's comfort in the fact that the FSS demanded only two services in the same mileage that many vehicles with fixed maintenance intervals would have required four.

Not even a month later, the ML's unfortunate confrontation with a pothole gave one staffer the opportunity to test Dunlop's run-flat tire capabilities - except that Dunlop has yet to produce a run-flat tire. The tire was a shredded mess before we were done with it, requiring a dip into petty cash and a date with the yellow pages.

Needless to say, we're looking forward to spending our last three months with the M-Class, its engine and everything it has to offer: great performance, outstanding dynamic ability, noteworthy efficiency and steadfast reliability. If one needs to ask for anything more from their sport-ute - and its engine - we don't know what it could be.