Well all those part numbers are the same as my front wheels! you should have BMW in between two wheel nut too, probably just out of shot on your first photo
Regarding brakes, I'm about to fit Porsche brembo 4 pots all round like mattcslnutt. They are as good as a direct fit using easily available parts:
Front calipers - boxster S front pt # 996.351.425/6
£320 ebay
Rear calipers - boxster rear pt # 996.352.421/2
£180 ebay
Pads of your choice, all available .........
Front & rear caliper mount brackets
£300 http://porschecalipers.co.uk/uk/81/p..._upgrade_.html
You will have to spend £50 for a bit of simple, obvious machining to the calipers to bring the pad over the whole of the disc face but apart from that it's easy. I have new genuine discs all round which you use with this conversion anyway which is a bonus.
I am going to paint strip mine and repaint them with £10 ebay red caliper paint and £5 BREMBO decals as I don't want porsche on them. I did this in 2003 to my VW campervan 968 brembos and they still look like new after a wipe down
You could have them powdercoated as this paint MAY not stand up to the extremes of the heat generated from tracking but it's always a good idea to do a 'warm down' lap anyway to cool the parts down as opposed to parking up right after a few laps and leaving them to bake!
JUST an opinion on a variation of the above recomendations, depends on how much you want to spend. My reasoning was if Brembo calipers are on Porsche, Ferrari and Lamborghini's (agreed bigger versions in some cases) then they are good enough for my CSL