[wtwo3]

I think M340i, C43, S4 etc are absolutely enthusiast targeted cars. Why would a non-enthusiast ever purchase them?

I define an enthusiast as someone who places higher value on their car/driving experience than the average consumer, for any given class of car. So in the midsize luxury sedan segment, if you don't place higher value on the car/driving experience, you have absolutely no reason to purchase an M340, C43 or S4 over a 330i, C300, or A4 respectively. It just wouldn't make any sense.