Windows.....

Hi guys and girls, how many people here have fitted windows to the sliding doors on there Vivaros?
How hard would you say it is to do yourself? (I'm quite happy to give anything a go but a little forewarning would be nice )
How much did people pay for the window kits and where could i get the best deal?
How much cost difference is it to have someone do it for you?
Is there any specific tools or bits of kit I will need to make the whole thing easier?

Thanks in advance van people and happy...

Windows.....