Hi LFN,
No, they're not LED's. LED bulbs are too white and make the
HID's look yellow. I just checked (this very moment) and I mounted the Xtreme bulbs. I think the Platinums looked yellow next to the
HID's..... The Xtreme's aren't ultra bright, but the colour match is better than all the others that I tried.
As for the other bulbs, I can't comment.... PIAA bulbs are very expensive and don't last very long (I know from experience), I think that the quality and range of other manufacturers has been proven to be much better than PIAA when it comes to main/full beam headlight bulbs.
Osram Nightbreakers are good, but Philips X-Treme power were proven to be the best on the market by Auto Express Magazine's tests. I'd choose these over PIAA every time (apart from the side lights!)