I'm assuming you haven't autocross yet, I'd just get a decent power train in there and start taking it out and get the chassis sorted out and build the engines as you improve so you can build the powerband and level where needed.
I've autocrossed a bit with my daily driver (2011 Scion tC). It's completely stock except for some Michel Super Sports up front and PS2's out back. The stickier tires up front definitely help get the back end around more. I've done about 3 events in the past 4 months (that's including the one I'll be going to tomorrow). I did about 2-3 last summer, but now since I'm out of school, I can make it a monthly habit. I'm definitely not the best driver, but I've been getting better.
Chassis, suspension, wheels, tires, brakes on the Dart are ready for power. 6-point cage is almost done and subframe connectors are going to go in.