I swapped out the original 7 leaf for a VB&P 360 fibreglass spring @ 10yrs ago. With the fg springs the shocks that you choose are very impt. to eliminate bounce. I went with Bilsteins front and rear. Both ride height and quality is excellent, I would go this route again. From what I've read the TRW glass springs make the rear ride height too high (gap btn tire and fender). VB&P are no longer in business so make sure that you ask the vendor who the mfg/supplier is.
If you were happy with the ride before your spring got tired you can always have it bent back to original arced curve and save quite a few $.