GT never got the DBW.
because you are forcing air in so the cpu might want to shut it down early and throw a cel light on
um nooooo, There isn't any very good tuning options available. I know SF has a kit out for the 2003 but it doesnt make enough power yet. you cant use a power fc and nothing else works too good.
So, yes you can turbo a 2003, we have one on our team. You just wont make as much power as a 2000-2002 model.