Tires are one of the most important changes you can make. They are also a big investment. You should pick up a cheap garden sprayer to cool off your tires between runs. I am sure you saw others there with them. Once the tire overheats your traction starts to drop. It is a balance of keeping the tires warm enough to stick well without getting them too hot.
Are you running wheel spacers? If so, don't race with them. They widen the track which increases turning radius. On the rear, they will keep the car from rotating in the corners. They are fine on track days, but autocross they are slowing you down.
Your lines look good and I see you are much closer to the cones. The more seat time the better. It sucks it is a police training course so you have those painted lines distracting you, but at least you have a place to race.