Not to question your expertise in the matter, but :D - are you sure the '98+ sc300s have the A341E automatic transmission? From what I read around the internet, and a few other people, the A340E (the same one in the NA Supra) is used on all sc300. I hope I'm wrong and your right, cause I want to turbo my '98 sc300, and having a tranny that can handle the additional power would be great. Is there really a big difference between the A340E and A341E? Oh here's a link that list the sc300 automatic transmission. I know the LS400, SC400, and SupraTT uses the A341E.
http://www.rebuilt-auto-transmissions.com/...id=465&l_make2=