Guys be carefull about what wheels you go for, I spoke to a dealer that told me they had a subaru in that had a set of BK 121, the car hit a pot hole and the alloy split in 2. The BK's are an imitation of the Meister wheel, and hence they are cheaper. I spoke with wheelmania about a new set of alloys for my E6 and they told me to stay clear of them. I was a bit suprised however about the comment about the Meisters discolouring, this happens to most alloys if brake dust is left on for any amount of time but these wheels cost nearly £3k so you would expect the best quality. Try BBS, Blitz or OZ, these are well know companies with a racing pedigree so they should know their stuff.
If in doubt stick with what you have as it is tried and tested, or it could be an expensive mistake.