You will get a more experienced answer in a minute no doubt but I have Yoko 032's on my 7. It is a 1.6KSS and they are great in the dry whilst you have to be a bit careful in the wet. I have not driven on 21's and some people like them.
It will come down to how you want to drive in the wet, how often and your own personal preference.
A slowly increasing number of photos here plus a shameless link to my company as I cannot do it from Blatchat