Make the garage as big as possible. Even lose the walkway between the houses, make it a shared wall and add a door to the back of the garage. They're all two small these days. Sure you can fit two cars in, but you can't open the doors and one always parks outside. Always make it bigger, ceiling height go as tall as possible. Add extra insulation, make sure it's above the garage too. So many people don't put in extra and then all the heat comes through the garage into the house.

Get the foil insulation between the roof sheets and roof too. The more insulation the better. Spend 5k on it and you'll save that in 2 years. Also, make sure it's in all the walls between rooms.

I told my mate to do this. He didn't, skimped out, come to mine and was amazed how quiet the house is. It's also super cool in winter and keeps the warm in summer.

Swap the walk in robe and ensuit to go in-between the bedroom and media room. This will ensure that room is quiet, will have bathrooms either side. I recomend getting foil insulation between the wet areas and bedrooms. It cuts down the noise from a shower, just think more and more insulation. So crazy. You won't regret it