Pistons; Cast or Forged?

[SkyFive]

When I built my engine last year I reused the old Wiseco pistons, rings and cylinders dispite knowing they were scored and out of tolerance. I've been getting some smoke on acceleration and besides that I'm having trouble sleeping ever since so I've decided to do the top end this spring with new pistons, rings and cylinders. I've done some research on cast vs. forged, both having positives, negatives and price is almost equal. My main concern with forged is the weight and shrinkage. Can someone tell me how much heavier than cast they are, how much do they shrink and how fast do they shrink. 

[ribbert]

I rebuilt my motor 15,000k's ago with Wiseco forged pistons and have none of the "rattle" I was told I could expect, especially when cold.  I weighed the old (original) and new pistons and the forged ones are approx. 40g LIGHTER - each!
Noel