i really wouldn't bother unless you are running a high performance engine or just like the look of them, they are thermally more stable so wont "squash" as easily.
ebay seems the obvious place but they are expensive compared to the original equipment. The original hoses on my 2005 TD4 lasted 100,000 miles before they needed changing so i just bought the LR genuine parts from Guy Salmon.
I've got a set on our TD4, no real performance difference on a normal car but got them thrown in on a deal and fitted them for peace of mind as less likely to collapse internally.