Nothing worse than washing 220M's after a couple of months (which is where I'm at). SONAX + power washer + Daytona wheel brush is tolerable. But I'm with the OP, love having a squeaky clean car, hate washing it though.
Current: 2008 BMW M3 Sparkling Graphite/Bamboo Beige/6MT. 1999 BMW M3 Techno Violet/Dove/5MT. On the list: BMW M2 Long Beach Blue/Black/6MT