If this afternoon Ford started spitting out brand new SN95s with Coyote motors and T56s for for $20-$25K, I would be in line to get one.
The reason I bought my car wasnt because of aesthetic or any other reason than to get a 400 hp manual RWD factory car.
I owned both a 96GT and a 99GT and would drive a 3300lb SN95 or new Edge all day over a 3700 lb S197 given that both cars had the same driveline.
The reason I didnt go with a motor swap is that its very hard to get a factory fit & finish and reliability with a motor swap. There is a lot of mix n match and fabrication involved and then you still need to tine for driveability and ensure all the elctronics are working right. It can be done, but its not a simple drop in the motor and trans
So yes, if Ford produce a brand new Coyote powered S95 or New Edge, I wouldnt hesitate for a second to buy the lighter car over the piggish S197 or S550.