I wouldn't replace the foam in it. Its good for a little sound proofing but it'll get wet again and wet foam is not good. There's no real need for 3/4" floor but if that's what you want go for it. The only problem I see with it is making it fit back in. Are you planning on taking the top off? Local lumber yard is where I found the best pricing for wood for me - HD or Lowe's just mark it up from their prices.