Well, as far as the CT20 goes...i know it is used on older turbocharged Land Cruisers in Japan. The CT26 was used on Celica All-trac's, MR2 turbos, and MKIII Supras. The Celica&MR2 turbos were the same. The MKIII Supra CT26 is larger, at least as far as the turbine and compressor wheels go. It would naturally need more flow due to the 3 litre 6-cyl as opposed to the 2.0 4-cyl.