The light output should not change much unless you changed to tinted bulbs. When I got my projectors off ebay it was hit or miss with being sealed well. The first set had one that fogged up and the second set was perfect.
I also bought a Audi A6 HID kit which includes OEM Hella ballast, OEM Philips/OSRAM D2S 4300K bulbs, H7 adaptors. The ballast fit perfectly into the slot on the back of my projectors and the wiring was fairly simple. I paid less than $500 total for the projectors and the HIDs and it was by far the 2nd best upgrade to that car, first being a chip.