The factory T/A spolier has a concaved base. So, when you look straight down, the gap shows about a 1/4" of paint, but when you kneel down and look at the base as it actually touches the trunk lid, the gap shows about a 1/2" of paint. Does that make sence?
ps: you will need to trim out the underside of the spoiler at the mid point if your trunk lid is not flat. Didn't they supply mounting instructions?