Left arm reject
http://hubpages.com/hub/Halo-3-Armor
No, there is no armor in Halo 3 that has a knife in the shoulder.
There is no Brute armor in Halo 3, only Elite and Spartan models.
go to http://hubpages.com/hub/Halo-3-Armor
you get all the vidmaster achievements on halo 3 and halo 3 odst
NO
beating the campaigne on legendary is a fast way of unlocking most the armor. some achievemnets also unlocks armor.
recon armor
the same way in halo 3 because when you play halo 3 mythic it says your playing halo 3
The most popular halo 3 armour is most likely the recon armour that you can get for your spartan by completing all the vidmaster achievements in halo 3 and halo 3 ODST. the least popular is the CQB armour, a.k.a the Close Quarters Battle armour
there is no permanent cheats in halo 3. you need to unlock them by achievments. and, you can not get the flaming armor effect, it is only for bungie employees. in halo reach, buy the legendary package to get that armor effect.
no