I bet it is the front tires hitting the rear of the fender well when turning. The '98+ rodeo/amigo has a smaller wheel well and tires hit pretty easy. The best way I found to make tires fit is by cutting off the bits of the car that get in the way of the tires.
Since there is no real way to lift the front of your isuzu, cranking the t-bars may or may not help because you will still be able to compress the suspension the same amount as a stock vehicle. It might rub less, but it will still rub if you hit a bump while turned.
Wheel backspacing is pretty important on the newer rodeo/amigo and I bet your problem lies more in wheel backspacing than anything else.