nice,, as racerf1 has answered all of the query,, one thing you should note,,that yr muffler should be towards grd,, not upwards. as you dont cyclists behind you inhaling fumes,,plus windpressure pushes yr car downwards from rear no upwards and yr exhaust should point to direction of wind (eventhough this dont make any sense.lol),, third,, you will get extra water in there while washing car,, 4rth,, you already noticed in most stock cars, the exhaust is facing towards grd.