Were your steering knuckles/hub uprights (names used interchangeably) broken or damaged? As
@Ark :D stated, the TC donor parts are different than the other Cobalt model donor parts. The lower ball joint mounting hole in the TC is larger (0.805 inch) than the others (0.750 inch). The uprights have to mate to the TC LCAs (lower control arms) that have a TC specific ball joint with the larger diameter stub.
BUT, the non-TC hub uprights could be modified by drilling out the lower ball joint hole larger - from the 0.750 inch to 0.805 inch size - if you are using the TC LCAs. The other item
@Ark :D mentioned is the brakes being different, based on the caliper mounting holes locations. DF will/has supplied the calipers specific for the TC application.
Keep us informed what you plan to do and ask questions - we are here to help.