What you are still getting is EBD, even though TC and VDC are off. You can still autocross with it turned "OFF", just don't do a lot of trail braking or the system kicks on pretty violently.
I have gotten my '12 stuck in the mud, greatly sucked. Did not matter if TC/VDC was turned off or on, had to get pulled out. OEM 15" tires are terrible!
But you can autocross, my video from when I got the car, TC off, OEM 15" tires, CVT--