I'd recommend getting at least a few 45° and 90° fittings. It allows you to make the loop so much neater.
e.g.
http://www.coolerkit.dk/shop/ek-af-angled-4624p.html
http://www.coolerkit.dk/shop/ek-af-angled-4625p.html
As someone else said, you should get 2L of coolant. You'll probably use around 1L, but it's better to get a bit extra than to be ~100ml short, and you can use the extra for top-ups in the future since coolant tends to slowly evaporate out of the loop if it's not perfectly sealed.
Unless you get an SLI watercooling connector, it's going to be tricky to connect the graphics card blocks, and won't look as neat.
You'd need 2 fittings like these
http://www.coolerkit.dk/shop/ek-hdc-fitting-4482p.html
and a rigid acrylic tube like this
http://www.coolerkit.dk/shop/ek-hd-tube-4486p.html
(how long depends on how many expansion slots will be between the cards).
Other than this, I'd say you're good to go. (I assume you already have all of the fans).