I used a XenonDepot PnP for my Volvo. That install, apparently, was made more complicated by me. I really wanted hidden ballasts, so when I opened my engine bay, the Volvo techs (during one of the many times I was in the shop) didn't see them...not that they seemed to open my hood to check my CEL anyway.
Anyway, the kit I got (I didn't get the Extreme kit, but the regular kit they sell) came with everything I needed. Ballasts, bulbs, and harness.
Install took me about two hours, though you can probably get it done sooner than that.
Edit: I would like to disclaim that I'm a firm believer in retros.
