Insulating a finished basement

[CarolinaCy]

So I'm getting ready to start finishing the basement in our new house, and I have a question for everyone. Since it's new construction, it already has the plastic covered blanket insulation around the foundation walls. The question is, can I simply leave this up and frame the exterior walls right up to it, or do I need to take it down and start from scratch?

I talked to two different guys I know in the construction biz, and one said leave it up, one said take it down. Thoughts from those of you who have dealt with this before?

[guitarchitect7]

Quick question,

do you have the 2" foam insulation on the outside? Does it go all the way to the top of the foundation wall, or only up to grade?

[guitarchitect7]

Ideally, the attached picture is what you want.

The issue I was alluding to above is sometimes homes are already insulated from the outside, in this case you wouldn't want to insulate from the inside as well, you'll just end up trapping moisture in the walls. Instead, just frame an 1" or so away from the wall.

[CarolinaCy]

I don't know for sure if there's insulation on the outside of the foundation, but I highly doubt there is.