In the past I've purchased from superbrightleds too an they're not bad.
However, for the Z I purchased LEDs (and 8K HID bulbs) from a vendor here called JWMotoring, and look really good. Here's a link to their site:
Nissan 370z LED Light
Here's a comparison of old (left) vs new (right) on my car:
The light is similar in color to a 7k or 8k HID. They don't look quite as blue as the pick makes them out to look (Photography is not one of my skill sets unfortunately) but they are really bright.