The angle that you should never mount the shoulder straps below is 45 degrees. If you were ever to get in an accident, and your shoulder straps were mounted at a smaller angle, the harness would be pulling downards on you as you moved forward from the impact, and basically compressing your spine downards. I had 5 points in my old CRX and only caught shit from 1 cop for them, but he let me go with a warning.
Look at this link and notice the angle in which they have their harness's mounted. Im not trying to correct you in a dick head manner, I just hate seeing people installing things imporoperly and risking injury, when it can be avoided.
http://p-car.com/diy/harness/harness.htm