Just my opinion but here's my take on wings for these S197s....
The no wing-look works great for that drag car look. No wing, skinnies, and big meats out back really gives these cars a no nonsense look...almost brutal.
The GT500 wing is the nicest looking wing for these cars without going too over the top. It's clean, follows and compliments the lines of the back of the car. The back of the spoiler angle out (mirrored) mimics the outward angle cut of the top of the rear bumper nice. Not sure if I described that right. There are many iterations of the ducktail-style spoiler out there but I feel the factory GT500 wing is the cleanest and best.
The stock GT wing looks cheap, just sits on top of the decklid and these style wings always remind me of the wing on a 1982 Firebird - just awful. Rather have no wing.
The GT/CS wings on the 2011+ cars are probably the nicest looking pedestal type wings I've ever seen and actually like them.
The Roush competition wings - although some think they are ricey, they are not - fit the car for the purpose and I think look good.
Regular Roush wing - sorry, don't like. They don't follow the lines of the car at all. Right idea, bad design execution.
Not on here to offend anyone, again just my opinion on styling. I went to school for automotive design, have designed many parts for the aftermarket for various late model muscle cars as well as styled a few cars that went to SEMA so I tend to let my design opinions fly. There's tons of sweet rides on this forum so please remember I just sharing my opinion and to each his own.