These exploits aren't really worth each of thier own threads, so I'll just jumble them up so its easier to read. Also, if you want to figure out what your modifier is, look at your character tabs,
1. Tabards/Shirts count towards Ilevel. I already posted this a while ago, but it still works with every vehicle modified by Ilevel average. Oculus, Ulduar, Wintergrasp, etc.
2. Being an attacking passenger in a vehicle increases your damage done, and health (Also, health increase is now only in effect when IN the vehicle, so the health part isn't important). You can see that there is a difference in damage done. I hopped into a friends demolisher in Wintergrasp, and noticed that my melee damage swings (as a mage) went from 500 even to 668. I later went into Strand of the Ancients as a passenger of a demolisher, and noticed on the same target, when I hopped out of the demolisher my Living Bomb ticks were doing 908 per tick, but when I hopped in they did 1100 or so per tick. This person didn't have a very high Ilevel either, the demolisher was under 100k hp. Now that people are decking themselves out in 264, 277, etc, gear, the difference will by much larger. 77% more passive damage anyone?
3. Spells can't be reflected back to you if you're on a demolisher. So cast away! Nothing can stop you while you mow people down =)
4. Oculus Mounts can be buffed. I had my mount buffed with PW:F and it went up over 20000 hp. I'm guessing with commanding shout, mark of the wild, and other buffs you could get a super-mount =). But with just a single one it makes the entire instance much, much, much easier.
I may add more tonight, after I get back from work. Depends on if people scream useless or if people like vehicle manipulaton.