Having own quite afew 8vers I love them they drive very responsively in traffic and around town!
Now if you got roads that are long and you can get past the 4K mark in revs then the 16ver comes into its own without a doubt.
I love 8vers and never put one down, but for faster crusing i.e using fith gear more the 16ver all the way.
The only thing I wish the 16vers had a standard were G60 brakes because for some reason the loons that I take rides with in 16vers brake really late and sometimes feel like brown trouser moments.
The question is the real difference it makes on a 16ver is sticking coillies on to them so they bloody don't rock n roll too much plus gives more grip aswell, proberly due to the extra weight it really kills the ride for me in 16vers IMO.

Jay