yes it will be getting the stage 1 c2 power turbo soon and i am trying to figure out the most performance and strength i can get the automatic tranny to have and im not familer in how the lsd bolts on and it would be cool to have since it help in getting out of corners quicker, guess the only thing to do on the auto is the level 10 torque converter...that sux.
They make a phantom grip kit for the auto GTS, that's as close to an LSD as you're going to find, it converts the factory differential to a limited slip unit. You can get it here; It's not an easy installhttp://www.phantomgrip.com/product_lists.php?make=Toyota
JMO is a good source for a torque convertor:http://www.jmousa.com/us/flash/frame/index.html
And Lastly, TurboEast's ESK (Electronic Shift Kit) for the IS300 is supposed to work on the GTS autos, when configured to switch on at wide-open throttle.http://www.turboeast.com/products.asp?page=IS300ESK
good luck with your project.