RE: Muffler bolts
The muffler is at minimum torque when cold. It will tighten with heat as the aluminum expands as previously mentioned. If you go just a litle past snug when cold, that will leave enough stretch in the bolt to allow for expansion when hot. Locktite is handy to keep the bolt in place, because the oil from the fuel along with the muffler's vibration is bad about rattling it out.