I always felt it went like this:
20-30 years old: 3 series
30-40 years old: 5 series
40-50 years old: 6 or 7 series.
I always thought this made sense (typically, but there are exceptions of course) due to the typical rise in income, size in family (20-30 usually single, 30-40 younger kids, etc), etc. but with how good the 6 GC looks, I'm not surprised the younger kids are trading up for it! I myself will be getting the 640 for my 40th bday...been driving 5 series for last 9 years. Right according to my schedule!
