mate, this bloke is obviously a complete nob! If it was me, i think i'd go as far to say that he would not of got away with it if it happened to me! The cvnt would be drinking through a straw after i finished! Was gonna suggest that u just go round his house and cut his brake lines, but the dumb fuk has got kids, so maybe not the best idea!
On another note, it is the ceramic from the spark plug that causes the glass to shatter. Maybe paybak on all 6 of his windows would be a better option!
On yet another note, look at his mates cars on his bebo wall! They're all s**t.