Aside from legalities, the biggest thing you need to watch out for is the combined wattage of both LEDs that will draw from your electrical system. Typically you'd want to stay around the same as the factory wattage rating at 35w.
And I will echo the above posts about illumination. I have tried LED setups on my cars but did not get the desired output. Brightness was comparable to halogen but the beam pattern was very narrow and do not light up the sides of the road. This is just the nature of LEDs as they are very directional.
Wiring should be straight forward. I don't know what that kit includes, but if it come with a wiring harness make sure it has a relay that you can connect your switches/battery to. You might have to make a custom harness if it's not direct plug and play. I have done many wiring installs so I like to keep aftermarket wiring separate from factory stuff, with connectors, just in case I want to remove later on.