1. because most car people don't like the rotary shifter
2. the DCT is a shift-by-wire transmission (electronically controlled), but the 10 speed in the GT is shift-by-cable (has a physical braided wire cable connecting the shifter to the transmission.
These are for the lower corner "grills", right? Isn't the driver's side more restrictive? And the passenger side is normally blocked off because the PCM is right there. With these you'll be soaking the PCM everytime you get the car wet.