The biggest disadvantage with a na coyote compared to the Terminator is its lack of low rpm torque. Even more so with the GT350 FPC set up too..... I drive my brothers 335 BMW and it feels faster and more zippy in daily driving.... But my Boss can destroy it every which way. But in a quick spirited drive, the 335 feels faster.
That is a good point between the terminator and s550. It is certainly easy to make the s550 put down the same power numbers as the terminator. However, the terminator will always feel like you are going faster. Goes back to the point of a raw and aggressive experience versus one that is more refined.