I got a sf bumper and i sanded and primered 120 grit. sanded and primered 180 grit. Before i do the last step i was wanting to make sure it was 360 grit. also has anyone put on there razor sides skirts? it looks like they are a little short and i don't feel like lengthening <---? them. How do you go about putting these on screw them in from the bottom? sides? just really wanting help on putting this kit on so i can go to the paint booth