Should I get my Hyundai Tucson's full timing belt kit replaced, including tensioners and idlers, or just the belt alone?

I have a 2-litre petrol Hyundai Tucson due a 50,000-mile service. The schedule recommends replacement of the timing belt, which the main dealer will fit. However, a non-franchised dealer recommends a full timing belt kit to include tensioners and idlers, which is beyond the Hyundai spec. It ends up that there is very little in the price between the two garages, because the timing belt kit is expensive. Will it be a false economy just to have the basic timing belt replaced as per the Hyundai spec?
If the car is out of warranty, then the more you can get changed for the same amount of money, the better. Failure of any part of the mechanism, whether belt, tensioner, pulleys (or the water pump if driven by the belt) can result in the belt coming off and valves hitting pistons.
Answered by Honest John on

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