Lotus spent many hours engineering its cars as pretty much every car company does. Once you start messing with things like wheels size, offsets, and camber angles you are then messing with engineering. Even tire pressures are engineered and tested for the best performance on every car from a Honda Civic to a Bugatti Veyron. I get a bit testy when some high school drop out at a tire store tells me I need to inflate my tires to 32 psi in my Elise to save on gas when the Lotus engineers call for 26F or 28R.
those volks on the otherhand, and boss. had i been informed that a better lotus fitment was going to be available soon, i would have gotten those instead of the cup20 wheels. love the cup wheels though. so light.