DB300s in my experience are very good at handling heavy-duty work, its just the DPF filters can get clogged up quite a bit (I know it's not in production anymore). I agree the B5TL isn't good for motorway work or any high-speed interval work, 240HP and the 918nm of torque just doesn't cut it. Couple that with all the equipment onboard, tables and passengers, it will stress the vehicle when loaded thus providing a laden feeling ride.

Problem is now with all the weight-saving dribble and lower emissions ect, vehicles are nowhere what they used to be. It's a false economy as vehicles are now less reliable and need replacing/upgrading sooner.