both companys i've had my deafner insured with both required engineers report for the lift and winch bumper, there is history of people and insurance companys dispute over the change of air to steel, unfortunatley the precise reference or tech yerm i'm unable to recal, its such a lot of nonsense ther's been rangerovers running on steel springs forty years,, ins company's seem to be looking for a reason to rattle up policy's for the slightest little thing these days, i have been ooohhhhd and aahhhd over fitting mud tyres WTF, my advice would be to declare it, that way they cant hold it against you later, the term you need to learn is it's still within manufacturing parameters