I have a nice road bike and take long group rides.

My problem is that I have not place to stow cloths and the like.
When you start the ride it is normally colder and you might need a extra layer or rain jacket.

I was think about getting a handle bar bag http://www.performancebike.com/bikes...&top_category=

But have a few concerns:

1) Does it have a big aero impact?

2) Is it just to fred?

3) What other brand bag?

Please feel free to provide other suggestions.