There are numerous debates on here about which is best, Halogen or Xenon. Speaking from my experience with both types of headlight, I can honestly say that any advantage Xenon bulbs has over Halogen is usually
irrelevant if you swap the manufacturers halogen bulbs for any of super breed of halogen bulbs, (Osram Nightbreaker, Philips X-treme etc).
I did this upgrade on my previous car, (Ibiza Cupra 160 TDI), and the improvement was fantastic, defenitely on par with my Lag Xenon's, my mates Astra Xenon and my managers Civic Xenons.
As with a lot of things... personal opinion is never universally constant.
Back to topic, I will be doing the aftermarket ballast swapout tomor, and I will be taking some pics. I will post the results and if it would be helpful, I could compile an illustrated guide if anyone is interested. If we can all change the Valeo sieves, (oops, I mean ballasts), to sealled aftermarket for less than £40 and maybe without removing the bumper, (for the n/s), then great!
As Fobskid did, I intend leaving the old ballast in place if I can get away with leaving the bumper on. If it has to be removed, I will uninstall it.