ct20b is not 100% bolt on, core is different size so oil and water lines are slightly different.
But a ct20b for a 1HD-FTE cruiser is a good OEM upgrade over a ct26.
Smaller turbine, so faster spool.
Larger compressor, so more airflow at same boost, and capable of slightly more boost.
There's an Aussie Facebook page "1HD-T tuning page" that's worth searching for a used 1HD-FTE turbo