Hi Uberprutser
Note that Crop will not put the clip back to its original frame size. if you set an AR to the Crop effect the frame shape will take on that aspect but there will be black borders as cropping inevitably removes part of the frame. The image will not be enlarged to eliminate them
On the other hand using the Zoom effect, VP will enlarge the area chosen to fill the frame. This means that if your original clip was 16:9 and you use a 16:9 AR for the zoom the image will enlarge to the zoomed area and subsequently fill the frame. Zooming will, in effect crop the frame. If, however you use a different AR to the original clip then you will have black borders either at the top or bottom of the frame.
If, after stabilization you see black borders, set up to show dual preview displays in Options/Display and then scrub through the clip and stop where the widest black border(s) are present in the Sequence Preview window. Add the zoom effect and set it to retain the original AR (e.g. 16:9.) Now, in the Clip Preview window drag one of the handles of the white dotted rectangle inwards to eliminate the border. If required, recenter the zoom rectangle and readjust it. It's not always necessary to recenter the box, that's up to you. The zoomed clip will remain full frame and as you have eliminated the largest border produced by stabilization the clip should be perfect when played.
Nat