seems easy enough, there are 2 wayshttp://www.toyotacelicaonline.com/shiftermod.htm
5th Generation Shifter Modification
Below are the instructions for using the stock shifter from a 7th generation Celica (2000-) in a 5th generation Celica. This will give a quicker smoother throw for a fraction of the price of buying or importing a shortshifter from Japan. These shifters can be found quite cheaply from 7th generation owners who have installed a TRD shortshifter in their car.
Preparation of the 7th Generation Shifter assembly
When you get the 7th Generation Celica shifter it is encased in a large plastic housing. On the top of this housing is a small door/hinged cover type thing(for lack of a better term).
Cut the cover in half with Dremel or another type tool. After the cover is cut the two sides will swing up.
On the side of the plastic housing there are hinges and springs, and part of the shifter itself runs through a lever, it is held in place by a pressed on plastic cap.
Pop off the cap...DON'T LOSE IT!!! YOU REUSE IT!!!
----To do this just put sideways tension on the shifter.
Rotate the levers upwards until the shifter is clear, and put it aside.
On your 5th Generation Celica
Remove the shift-knob, shifter cover, shift-boot, and foamy thing(if you have one).
See the little metal cover with three 10mm bolts?? take it off...DON'T LOSE IT!!!
Next there is one of two shift rods. This is on the drivers side of the shifter. Remove the cotter-pin and teflon sleeve...DON'T LOSE IT!!!(see a theme here?)
Next are the four 12mm bolts holding the assebly(sp) to the frame.
Now the second shift rod, this one is underneath, and held on by the mother of all cotter-pins...DON'T LOSE IT!!!
The whole unit pulls out.
Repeat steps 3 and 4...there is a spring on the side of the housing remember how it sits, it is important.
Once you get the old shifter out of the housing, pull off the old friction cup...but don't damage it, or the gaskets...YOU WILL REUSE THEM. But you DO need to clean the cup.
Take the Y2K shifter and 5th Gen friction cup, grease them with a Silicone based lubricant...if you don't have a Silicone base, white lithium grease will work fine. Use liberally.
Reassemble everything in the reverse order in which you took it out.
Check for clearance, space if needed...shift away!!!