Does anyone know the pros and cons of putting in basement rooms,e.g. bedrooms or shower would it more cool but yet more costly and more hassle to do?

Not an answer to your question just a positive comment.

My wife and I paid a visit to a Thai lady boy friend who had a great looking home, The home could hold its own with many in the States. He then wanted to show us his special room, which was a very large basement room, very cool and it was his gambling room where he and his friend could gamble with no worries from the police.

As we drove home my wife made the comment that she would never go in an underground room, it was just too scary.

Only basement room I have seen in Thailand and it looked neat and cool. No idea on price but it was a very expensive home.

people usually go up in that area, due to the rain factor and most likely the soil and everything. as for going down? not sure.. i think it will cost quite a bit for water insulation humidity....