Mine cost £3200 at an independent garage and took 6 weeks!!! The problem is the quantity of parts you need and the availability from Italy;-
3 x chains
5 x tensioners
Possibly 6 sprockets
Coolant. etc, etc.
I looked into sourcing in the USA and could not be 100% sure that the parts were identical, plus not all the parts are available.
The job is a btich to do in the car and worse if you take the engine out, especially if it's 4WD. Labor costs are huge.
Stuff breaks and snaps off whilst you are doing it and that all costs.
The best thing you can do is change the oil every 5000 miles to preserve the timing system life. BTW, it's not the chains that stretch, the pins wear and the tensioners are plastic nuf said.