You cannot make a quad street legal in ohio,ky,or indiana, I have studied this exstensively.There are only a few states it can be made street legal in,arizona,and i think utah and one other.But dont quote me on what 3 states it is.
The reason for atv's not being legal in most (not all) other states has nothing to do with emmisions or being a 2 stroke. There are loads of 2 stroke street bikes that are legal in all states.The first prototypes of the dodge neon were 2 strokes. It has to do with wheelbase and not having safety equipment.Its because most of the dmv's view anything with 4 wheels in the same rules category as cars,and cars must have a certain wheelbase,seatbelts ect ect. This is why some trikes and 3 wheel machines like that bombardier 3 wheeler thing can be made legal,they fall into the motorcycle category and not the car.
I actualy used to chat with a guy who had a street legal banshee,and he said it was more of a pain in the ass than it was worth. he said he got pulled over basicaly every single time he took it out,and had to explain to the cops and show the registration.
There was also an issue of dirtwheels where they made a 450r street legal in arizona and did a road test.