Diesel chips for tow vehicles

Has anyone else had a problem with their insurance company regarding the fitting of a 'diesel engine performance chip'? Ours told us that if we fitted a chip to our 2006 Hyundai Terracan diesel 4x4 (increase in performance from 120 to 144kw and 345 to 414nm) that we would effectively have "hotted up" our vehicle and be classed as hoons. All I wanted to do was get better towing power for our two-tonne van. I rang other insurers and was told the same thing - they would not insure our vehicle.

Bob, Vic