for me sideways isn't an issue, i wen tsideways to the S2k, i've reached a level of motoring i'm happy with, if i start looking at faster beasts; the expenditure seems to go up exponentially. at this current level its still affordable to run as a daily driver, is useable and affordable.
and the advantage of the m3 is its going to give me the extra seats and space, more useable boot. but higher comfort levels than the z and by a long way the S2k.
the M3 is something i can cruise for long drives in lots of comfort and relative quiet. but when i've dropped the wife off i can thrash it round a track or the back roads.
yes a zed can kind of do that; but it doesn't have the space i need. or the level of equipment the m3 has.