Converting to Foam core stringers and transom from original wood affect the ride?

[Hugo G K]

Hi I have been studying seacrafts for a while now and finally decided to take on my own restoration project on a 1968 20 seacraft. With no surprise, when I removed the deck I found the wood in the stringers and transom have started to rot. I have decided to replace the wood with a foam core and fiberglass which will obviously reduce the overall weight. My Question is, by reducing so much weight by switching from wood to foam, would this affect the ride of the boat? If so for the better or worst? I am also adding a flotation bracket and closing up the transom.....
Please let me know your thoughts and suggestions,

Thanks