andrew replied:

hey mudguard, i have 96 gq 2.8td and i had i high flow exhaust 2&1/2 inch fitted from the flex pipe through to the rear. it cost around $250 installed and it made quite a differnce at high rpm. the turbo winds out alot more giving you a longer power ban and you can hear the increase turbo whistle. on the other side if you drive conservativly it runs more economical. another plus is it helps the engine run cooler. i would recomend it for sure.