Tire conundrum

Best option is to replace the rims. A 245/60/14 should fit that car no problem with the proper backspace.

Springs would be next, but I'd only do that if you aren't happy with the ride height of the car. If you like the car how it sits, change the rims. If its sagging too much in the back, then change the springs.

Shackles and air shocks are band-aids that will cause more problems than they solve.