For 90-93 the GT, GT-S, and All-trac steering racks are the same.
You can buy a remanufactured rack through the Toyota dealer. I've heard they're decent. Toyota gets is remanufactured steering racks from Maval. You can buy the Maval rack for less than the dealer reman. It's available from Worldpac. Search for W0133-1745725 and you'll find some online resellers. I put a Maval rack in my friend's Sienna, and it's held up well for the last 2 years.