Well interestingly, the Porsche instructor I spoke to most of the time hated the 16" standard 986 wheels. And I read that on the BMW Minis, the 16" wheel gave the best handling in a 15" to 17" range. As the manufacturers have to set up a one size fits all suspension (geometry, spring and damper rates, bushes etc.) do they optimise it for the middle sized wheel?

Another thing I've noticed is that Bristol use 18" wheels with 285/40 tyres on their Fighter, which is a 220mph car. There is no 19" option. Now that is a company who pride themselves on putting engineering integrity over marketing (and are all the more brilliant, if eccentric, for it). Makes you wonder if 18" is the best compromise with current technology.