thanks for the comments, i am running 285/75/16 muddys bf goodrich, and havent done anything to exhaust yet.is it worth the cost to put these 3 inch exhausts on that i read about in 4x4 mags. this 4.2 is not efi but mechanical so i am confused as i went to opposite lock in ballarat and they said you cant get chips for mechanical fuel injection, and a dyno would do very little as well, keen to hear from anyone if a dyno is worth doing. how do you check the boost and adjust it ,is this done on a dyno ?? thanks