not exactly,
offset defined: the distance from the centerline of the wheel to the bolt circle (the surface of the wheel that touches the hub).
positive offset increases that distance by pushing the bolt circle out- closer to the street side of the wheel, so you have more rim tucked under the car.
this would mean that my wheels should have fit just fine, and been sticking out too much from under the car. hmm. but like i posted earlier, i have 13 inch brakes, and i think the hat thickness on the rotor is too skinny for thunderbirds. (still have to find out about that)
so what you get when you put on the 03 cobra wheels is a wheel that sticks out too far (you increase your track), because your offset is too little. your talking like 12+mm on both sides, then with tire bulge and a lowered car (mines not) you would rub your fenders.
I wish i had some pics to post. with the spacers i put on my front wheels they are sticking out FAR. I measured. my front track is now almost 3 inches wider than the rear. i know front track is wider stock, but i increased it a lot.
you know i'm proofing what i wrote and its confusing me. i can't figure out why my wheels didn't fit right. well actually its only the fronts that weren't right. maybe it all because of my rotors.
anyway, yeah with 03 cobra wheels your tires will end up being outside the fender line in the front (like mine are, slightly, front only). that was the problem i came up with for those wheels, that would apply to all 4 corners.
anyway if you want to get em' try
www.buyfordmotorsport.com and
www.gefracing.com good prices
jim