As long as the rolling circumference of both sets of tyres are "equivalent", there will be little difference. For instance, going from a 235/45 17" tyre to a 235/40 18" tyre will be near enough equivalent.
Other small factors do have small effects, but I wouldn't expect them to be very noticeable. Tyre rolling resistance, tyre and wheel total weight, and drag from wider tyres will all be "small".
Rota's are heavy wheels? Your tractive effort will be massively affected and more power will be needed to turn the wheel to equal previous performance. Which is why drag. Are have tiny wheels, large tires and little pressure.