Interesting discussion on wheel size.
Just one comment on 20" is the comfort and ride quality.
I'm running 20" on my Jag XF and while lost people think it looks the dogs and I totally love them I can tell you even with it's sublime suspension greater wheelbase and comfortable sports seats, I can feel every pea sized pebble in the road.
The Zed with it's harsher suspension on current condition UK roads would be absolutely horrible :thumbsdown: