Suspension upgrades ,the best route

advantages are easier to dial in / tune for autocross
hemidenny kit with coilovers has no bump steer

biggest #1 most important thing is the rubber underneath, helps turning, helps with stability, helps braking, helps accelerating...
sway bars would be #2
springs/shocks would be secondary to the rubber and sway bars
rack and pinion is superior to the original steering, but you only get that with one of the suspension tubular kframe upgrades like hemidenny's