The wind deflectors are held on by the same stuff as the emblems (3M double-sided tape). As per crotchrocket's suggetion, after heating it up, like the emblems, saturate the adhesive area with Goo Gone, wait a few minutes, then use dental floss to start on an edge. Once you get that first edge lifted, keep spraying Goo Gone along while you slowly peel back. You would need to be mindful not to stress the plastic part too far too soon otherwise you may crack it! Use the floss, spray goo gone, slowly pull the part back. Repeat.
You'll eventually loosen up the grip of the tape and remove the part. Then with spray more goo gone to remove the rest of the adhesive remains and your good to go. Though, Goo Gone is pretty safe on most painted surfaces, I would first try a little in a small inconspicuous location to test it first. Good luck and feel free to let me to ask q's. rudy