sorry to bring this post back from the dead, but i felt i should mention something, catz is not good at all, in fact, go here to their homepage:
http://www.fet-usa.com/
they have a huge recall on their lights because they are in fact street-ILLEGAL. i agree with loveless, ive done hours upon hours of research on the internet and calling places, and going to places like hidforum.com and what i found is that when talking to anyone educated in the subject of lighting, there are 2 names that repeatedly come up as the brand to swear by, either philips or osram-sylvania. these are the 2 lighting companies that take pride in their product, and the only 2 that are trusted by oem manufacturers, you will see only these 2 brands on cars, all the way up to audi, bmw, mercedes, porsche, ducati, etc. so go with one of these 2 companies, save yourself the hassle, and remember that if you choose another company then it will impact not only you, but other drivers on the road. this is for bulbs themselves, for example if you have an s13 then by all means get the bosch h4 conversion if you want h4 lamps, but use one of the aforementioned for bulbs (on a sidenote, there is no need, both of these companies make their bulbs in basically every style, including sealed beam)