Another Muffler Thread

While I have the floor out to replace the stringers in my 77 Tique, I thought I should probably replace the old mufflers as well...then I started reading and eating the videos of people showing how great they sound with out mufflers. My only concern with removing them is that kids are usually the only ones sitting in the back seat. Will it be too loud for them?

If I do replace them should I stick with the cast mufflers like original or go with fiberglass?

I like the sound of stainless or copper straight pipe, but am not sure what sort of dB increase it will have.