I'd match Jake's suggestion, I wouldn't buy another set of springs- I had the 3800# springs on mine but it was a 4 speed car. Relocating the rear hanger should be almost free to try, I'd give that a shot first before attempting anything else.

On the original topic I wouldn't cut your car up just for inboard springs either. It's too nice. If you're going to fire up the sawzall, at least go big and back-half it.