Try lifiting on the accelerator a little on the up-shifts... you'll find it's much smoother -- Yes I actually own an '08 M5.... yeah it takes a little getting the hang of it -- but it's still about as much fun as you can get. I also own an '06 650i Droptop... lovely car - for the wife.... not sporting enough for me.
I also LOVE the Merino leather and up-graded seats in the 5 --- over the the 'sport' 6 seats - the 6 seats have 78 positions - and need 79... not so in the 5 -- wonderfully comfortable!!