Hi all, first post.

I have a 954px x 80px rectangle that I applied a drop shadow with a small offset to, but when applied the rectangle increased in width about 50 px on either side. Any suggestions?

that would be the "filter area bounding box". Basically there are different ways of looking at the size of objects.

1) the geometric size, eg the area crated by joining up the points of a rectangle using invisibly thin strait lines
2) the styled area bounding box. this contains things like stroke thickness and end caps
3) the filter area bounding box. Because filters use raster operations, there size cannot always be precisely defined. (think the edge of a blur) instead, SVG sets up an area that should be "large enough" to contain all the filters effects.

Inkscape then has to show one of these as a guide to the objects size. Inkscape normally uses the largest of the 3 available (the filter bounding box if it is set) as the visual bounding box, although it can be quite confusing as it can be much bigger than how large the object looks on canvus.

To change it to the geometric bounding box go File_> Inkscape Preferences -> tools