Please note tha the reason they come in 5 meter strips is because this is the maximum length that they can reliably be powered due to the printed circuit lenght and loss (from the manufacturer).
My former boss wanted to run a 20 meter length down the driveway for cars to follow and got upset when they ran wires to each 5 meter length claiming they 'just wanted to bump the cost up' had to have our electrical engineer explain that the start point would not support 160 watts through the 'itty bitty' copper wire.
Not a bright one my former boss!
Daz