Well, you're not really comparing like with like there. To do that, you'd have to compare your car with a Z4. Keep in mind though, my view is that BMs are one of the best driver's cars out there, not necessarily THE best. I haven't driven enough cars to form that sort of opinion but they're the best of what I've owned.I'd be curious to see how one of the smaller Beemers handle in comparision to my RX8, which is still one of the most enjoyable cars I've ever driven in a sporty context.
If memory serves, Clarkson did rate the M2 as the best driving modern M car in their Amazon show a few years ago.
Oh, and the word you're looking for is 'comparison' (soz, I'm on a roll ).