Do you think that is a pretty good setup or could you recommend better?

How much would a 2 to 4 plant system go for with a 600w HPS light system? I thought I was in the right ball park in price but I take it im wrong. I dont mind spending a little extra to get a good setup.

After looking at that setup it does look pretty simple to make. Would that setup require putting it in a grow box with ventilation or could you grow as it is in a closet?