as far as the weight goes you can google that!
When it comes to handling...anything with a shorter wheel base will have better handling...anything with a longer will have a smoother ride.
7 are not meant to handle corners at 143 mph rather designed for comfort with a hint of handling...but don't get me wrong they still handle better than their competitors
the 530 and 540 are two different animals...your looking at a doberman pincher ( has a bit and rather nimble) compared to a rottweiler (which has a lot of bit but not as nimble)
I hope all this helps
p.s. If I were you I would get the 540i M Sport 6 speed...then again I do not have children or other people to haul around and don't care about fuel costs...