To me "streetable" means pump gas, reasonable fuel economy, you can carry on a conversation while driving without too much problem, and you are not harassed by Johnny Law at every opportunity.
There is a difference, to me, between "streetable" and "can you drive it on the street". I have always viewed "streetable" as would the car function well as a daily driver. If it takes something other than pump gas it would not function well as a daily. Same goes for economy - while it is all relative a car that gets 2 MPG is not going to work well as a dail so, TO ME, it would not be "streetable".