| Based on my GP
215/35/18 gives speedo reading high by circa 5 to 6% versus circa 3% with standard 205/40 - test done with GPS and also relates to tyre size calculator info.
If and when I replace the tyres then I would go for 215/40/18 - speedo will be more accurate and I will not have the 6mm drop which is too low for the already low GP.
In Italy  | 
