It can be put back but is a pain because you have to take the top of the motor apart to get to the cooler which is under the intake and turbo - They are going to be starting to test diesels in california, Its only a matter of time before more states follow - You are right though, it takes the gov. forever to do anything 
like i said new and have a lot to learn. As for Cali you cant do any thing fun there, bada@# trucks with programers Arnold say NO, Automatic rifles Arnold say NO emeesions on diesle what is next? thats why it is the land of the fruit cakes or somthing like that!!!