As Celica wasn`t offered as convertible out of factory, lets consider this as a tuning option :) Maybe someone can share the conversion process?
I was inspired by this post today, so I searched up for a few convertible celicas
This is definitely the best of convertibles out there:

full thread here: http://www.alltrac.net/phpBB2/viewtopic.php?t=21030

Here is narrow body st185 with st205 engine and converted to cabrio:

http://www.gtfour.ch/driver.php?index=drivers&id=72&code=185