it would be ironic if diesels did have auto recirculate as the purpose of that is to eliminate all smog from entering the cabin in the first place, from diesels mostly.
My car is a 2008, with Mark Levinson, i seriously doubt you can put HDD onto this, I'm not entirely sure what Jack is trying to achieve here. I think what he should ask is can you put a facelift Nav unit into a 2008 is250? one that has a HDD? I don't know and it would be costly.