Gotta go round shaped to keep with the FTO's fluid lines. Only place there's anything even slightly squareish on the car is the tail. Then again, saying that might want the squares.
When going twin, You have to take into account the clearance to the rear of the muffler.
My current mufflers just fit in. I made sure i bought the shortest ones possible.
My new exhausts have to be angled out because they are a normal length..
Check this first. It will most likely severly limit your choices.
If you need good deal on photography, let me know.