season set is only for gp3_2K, you have gp3 1.13
try this:
-open the car editor and if you didn't it before, from the options locate the gp3.exe and the level of patch(gp3 1.13 in your case)
-click the green button with the red arrow to import the gp3 custom shape.
-import your .cam from the menu FILE
-export all with the button with the small blue arrow and confirm all the messages
-done
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