As long as there are no laws against them (like if they're blue, red, or something, etc) then they're legal. As for the difficulty, depends on how you feel about taking your lenses apart and putting them back together.
Oh, and at work, we sell them, I think they're $20 a pair. I bet most auto part stores have em, should be in the section with all the APC ricer stuff.
They're not for specific vehicles, they're universal fit. I'll get a pic tomorrow at work and send it to you to see if it's what you're lookin for. They should be about the same price at any Advance Auto Parts store around the country.
I found a link to a project for installing them on a Mazda3. I'm not sure I will do this, unless I get REALLY bored in Poland. I didn't realize the bumper would need to be removed.
i had them on my 97 sentra. this question is right up my alley.
they make them for spectic cars or trucks it is the whole head light. if you are luckly you might find them around $100.00 most of the time they are around the $300.00 range]good luck they are not out for the trac yet.