You have to find out what year the 1G FE gearbox is.
It could be the 6 speed made under licence for Toyota by Getrag for the Altezza / Lexus IS200. These came out in 1999.
OR....
It could be any old W55, W57 or W58 gearbox from a GA70 series Supra (for example) which did come with the 1G-GE or any other Toyota with the 1G-FE motor. My research found that the 1G-FE was made by Toyota well before the IS200 6 speed manual was sold by Toytota.
Given all of that....a W57 or W58 will hold up fine behind a stock 1G-GTE and be a similar or in fact cheaper price than the 6 speed box.