Basement carpet & pad
 

I just bought a house in the midwest, and am replacing the carpet and
pad in the basement. I am getting an upgraded pad, its not rubber but
some other type of synthetic that water cannot penetrate. Is this a
good idea? Or should I be getting some type of 'breathable' pad? The
carpet is just ordinary, inexpensive carpet. I've only owned the house
for a few hours, but it feels plenty dry down there. Its a multilevel
built in 1985, so I'm sure it was built with the basement finished, so
maybe it has plastic under the slab and I have nothing to worry about?
Most of the basement is really about ground level so maybe don't need
to even worry about it. There is a subbasement that is about 6 feet
lower than the finished basement (its next to the finished basement,
not underneath), and it gets a little moisture.

The standard pad was made out of some kind of recycled foam-looking
stuff, the stuff I upgraded to seems like a much higher quality
product. They aren't installing until next week so I can change it if
I need to.

Thanks for any input.
-Ryan