What did yea hit bud? I gotta redo mine already, ripped a hole in it by the exhaust.
3/16 bit, lots of speed, little pressure. Don't let them spin, if they do use vice grips on the backside and hold them. 90degree drill is the weapon of choice for the tight areas. Other times you can use a sharp chisel and hammer. Shear the back side and pry the rest out.