The problem I often hear is that the floors creak and pop a lot. The problem often is that when pressure is applied to the boards, they flex between each other. This means that the tongue is actually moving slightly in the groove and generating the noise. That, plus the boards actually move slightly vertically and rub each other. Read about a trick that I have used to solve this problem.
Building a set of wood stairs is not nearly as hard as you may think. With some basic wood tools and a bit of algebra you can easily build your own. Of course this can get a bit tricky for stairs with several landings but the method is still the same.