heres the reply I got when i asked them last night!
Dear Craig,
the warning on our website (and in our boxes) "not for highway use, road
race use only" is necessary because in many countries any modification of
the aspiration system is not legal. In fact we sell our products all over
the world and it is necessary to cover ourself in the opportune way as far
as the legal aspect. So dont worry, there is any controindication using the
CDA in common road.
Best regards