Just a random review!!
I had a headlight (factory) go out early last week in my 04 A4 and was contemplating about going HID conversion or replacing the factory H7's with an aftermarket bulb. The shop around where I work had the PIAA's in stockso I put them in and I think they are WAYYY better than the stock bulbs. Immediately noticeable.
I read several posts about PIAA's and Silver Stars and although I have nothing to compare these against, I think they're very nice.