Hi Arthur, I am the owner of AMMS mechanical at Sandgate and we specialise in 4wd turbo upgrades.I have a 100series turbo landcruiser with a chip and exhaust. There is quite a few chips to choose from all offering similar increases(Dtronic,Rapid,DP and Steinbauer to name a few). The chip alone will give you approx 10% to 15% increase in torque and power.Add a 3 inch exhaust and you will achieve another 10%(based on the 100 series).Another bonus is better fuel economy. I tow a 3.2 tonne ATV and the main advantage i noticed was the torque increase throughout the whole rev range. I can supply you with dyno graphs that will show increases and you can also take mine for a drive to feel for yourself. I hope this info is of help. Regards, Glen Hadden AMMS P/L 92 Connaught St, Sandgate 3269 6555