Crossfire six-speed trannys are notoriously stiff when they are new. Especially the 1-2 shift like you mentioned. Especially when they are cold. Getting into reverse is somewhat difficult as well. Things will start to loosen up as the tranny gets some mileage on it and the mechanical bits get to know one another better.

Personally, mine started loosening up nicely at about 20-25k miles. I'm at 45k miles now and it's silky smooth.

As far as vibration goes, I always feel a little bit, but it's not what I would call excessive. If you think something is not right because of the amount of vibration you feel, then take it to a dealer and have them look at it. That's why you have a warranty. It won't cost you anything but time. I just hope you can find a good dealer!