Step 1 and 2 good to start of with a solid suspension,
Why do you think you need springs before torsion bars,
Really as long as your car never bottoms out you can set up handling with just sway bars but it easier to spread the load between the two, the front end does 80% of the work I'd do front sway bar and torsion bars then work work on the back to make the car neutral no over or understeer or just a slight oversteer. Some setups don't even need a rear sway bar. Lowering the car helps a lot but requires more spring rate so it don't bottom out and don't go more than 1.5% rake.
After 1 and 2 on your list I'd go with tire cause tires make the most difference, big and sticky, then sway bars then torsion bars leave leafs to last to see what you need to balance it out.
If I can afford it, I will do torsion bars in step 2. I'll be working up a parts order next week.
I've got ok tires on the car at the moment (Republic Invader Radial GT) appear to be recent with no signs of unusual tread wear at the moment. I'd like to hang on to them while I weigh the option of going with larger wheels.
The great part about deciding to buy this Dart is that now I don't have a car payment, so I'm able to put a little bit of $$ into it every month. (ideally)