Sorry was out of town! I took some photos but my car is black so not sure you can see everything (sorry the resolutions stinks on these).
I will try to describe how I have mine because it looks different but has worked for the last 3+ years on my Caliber. One thing is mine is only a two carrier and my car has the standard spoiler. It does pull against it which looks really concerning but after 3.5 years and many bike trips I still have a spoiler. We went all the way to Little Rock dragging two bikes on the Caliber. I can't put it one without opening the gate so we might be doing something different. As you have probably figured out there are very few Caliber options short of a hitch (a bit pricey for me) or roof rack (I like my sunroof and pulling in the garage without thinking too much).
1. The top hooks are latched into the part where the gate hinges, does that make since? They are not in the spoiler but the metal of the gate that the spoiler is attached to.
2. The side straps are slide between the gate and side of car. We then use the adjustment to tighten.
3. The rubber rests on the glass and bumper.
4. We hook the bottom under the bumper, there are actually two holes to secure it but we found this by crawling under the car. DO NOT remove it until the car cools down, I burnt myself once having a blond moment. 
For scratching the guy at BSS recommended getting that thin foam to wrap around your pedals and bars. At 75k on my car I am not super concerned. The car has been dented by carts, scratched down the side by someone, etc... My husband is super attentive in loading them and uses the extra strap to tie the handlebars so they aren't swinging around.
Amanda
2011 Specialized Epic Comp 29er | Specialized Phenom | "Marie Laveau"
2007 Cannondale Synapse Carbon Road | Selle Italia Lady Gel Flow | "Miranda"
You don't have to be great to get started, but you do have to get started to be great. -Lee J. Colan