Noise level is not bad at all, my step father on his first drive in mine asked me if I was sure it was diesel (24 valve), he was convinced it was petrol until I opened the bonnet and showed him the engine because it was too quiet, more fan pulling air than engine noise on standard exhaust.
Economy is not bad when compared to other vehicles in its class, mine is a manual with 2 inch lift on standard rims/tyres, has winch and winch bumper with headlamp protection (formerly known as a bull bar), roof rack and tent/awning and I have replaced the rear bumper with a steel after market bumper, I have also fitted a intercooler to mine and tweaked the injector pump and turbo for a little more performance and with a heavy foot I average 22 mpg around town, 25 mpg motorway and if I use a light foot on the power pedal I have achieved 29 mpg on the motorway following the HGV's, but that is way too boring lol.
The engine is renowned for it's longevity when properly maintained and the when the vehicle is properly maintained then the economy is good, tyre pressures are critical for economy,
I once got 14 mpg on a run before I thought to check tyre pressure after tyre swap on all four rims, pressure too low
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The torque and power is something to behold.