I don't have to be concerned about insurance, the features that are claimed to be not allowed by the UN directive are active in my country in the most recent models and my country is a member of UN (and EU).
At the very least you'll need to declare it, because you'll be modifying the car from how it came from the factory. If you do not declare a modification, you are opening the door to a legal dispute with your insurer if a claim is made against the policy and they discover that the car had an undeclared modification.
If you do declare it, and there's a claim against the policy, then your in the same situation again if the insurer discovers that the mod was banned by a UN directive.
You might be prepared to have a long drawn legal battle with your insurer, and you might even win, but most people will just give the whole thing a wide berth.
Of course, if there's no claim, and/or the insurer doesn't find out about the mod, then there's no problem. It's only a question of how risk averse you are.
Personally, having been in IT for over 40 years, my appetite for risk is zero, and I have on several occasions bored to death the call handlers at Aviva with the full details of every minor modification I've made, including retrofitting puddle lights to the front doors, retrofitting a boot relase button on the drivers door, etc etc (the list is long

) ........
But, ultimately, it's the OP's car, and his choice. That said, I am still not convinced it's actually possible.... I will be watching this space
