Hey fellas, Jairo from Queens here! I'm glad to be part of the site. I was directed here from a member of mustangforums.com. I currently drive a '07 V6 slushbox but in the upcoming months hope to upgrade to a '09 manual GT.
Doable, yes. If you don't lower the car and go with the taller tires, you might save a few choice words.
I have looked at the side exhaust for a long time and asked many questions. If you look under the car you will see the floorpan just behind the side skirt, Subtract 3" from that height and that is where the exhaust sits. Not a lot of room. Check the pics of another member with that set up. keep in mind also, he lives where the roads are much better than queens.