If your car is low to the ground, you will need a jack and a pair of sturdy jack stands to raise it up.
You will need a power drill, and a set of drill bits. You might need a sharp utility knife.

Carefully unpack and test your underbody kit. Connect it to your car battery, and make sure all tubes light up the way they are supposed to. It is not fun to install an underbody kit only to have to pull it off because you found out something was defective.
Take some time to look over your car and make some decisions before starting. Figure out if you have any existing places you can mount tubes without drilling. Plot where you're going to place your ECU and remote display. Find grommets and other places to run wiring. This helpful planning beforehand will save you time and future hassles!

Jack up the car. Always use jack stands for safety!

Mounting the rear tube does not require any drilling. You can simply cable tie it to the bumper mounts. Be sure to keep the tube and wire far enough away from the exhaust line.

Run the cable through a rubber grommet, and into the car.

Find a good place to drill your mounting holes for the side tube.....

.....and mount the tube! While two zip ties will be enough to hold the tube up, you should always use extras. Here, five zip ties will hold this tube up nicely. Note! Make sure to aim your tubes to the desired glow effect before completely tightening it down! This may take a little while, as you might want to lower the car back down to see exactly how it will look at normal height, but we assure you it's worth it.

For the front tube, we drilled pairs of holes into the plastic engine cover just behind the bumper. Then simply ran zip ties through them and attached the tube! Easy and efficient (and you won't have a large gap from cutting up your cover).
After your tubes are mounted securely, run the wires to your ECU. Avoid suspension components, exhaust pipes or any other high-temperature sources, and other moving parts!! Also make sure to wire up the power and ground plug for the ECU. Remove the fuse from the power wire before installing, in order to avoid any slight accidents. Install the fuse once your entire underbody kit installation is done and you're ready to play!
Make sure all wires are secure and will not move. Also, you may consider wrapping all of the wires in wire loom. It is not necessary, but it is an added layer of protection from weather, rocks, and other hazards the underside of your car encounters. Especially for you people living in snow and icey climates!
The last step for running your wires is to mount your remote display. This can be anywhere you desire - on top of the steering column, on the dash, on the door, inside the glove compartment - doesn't matter. Make sure to hide all of your wiring inside your xB - it is not only unsafe to leave exposed wire, it will hurt you when showing off your ride at a show!
Once everything is wired up and mounted, pop your fuse into the power wire and go! Enjoy your new underbody kit on your Scion xB.
Check out the awesome FlowLighting Inferno Million Color LED UB Kit!