Ok om a better mood today, (=didnt kill any patients, and had no complaints...) there is a thread here and i cant fint it for the life of me.. but it shows a c5/6 rear suspension installed in a mid year corvette. but instead of using an adapter plate it simply used a viper diff instead, thar way you could mount the controll arms to your own cradle instead of having to dink arround with modifying the corvette stuff..
but since you are into the drifting scene.. how about widening your search of donor cars:
http://cgi.ebay.com/ebaymotors/JDM-T...Q5fAccessories
there are a myriad of drift specific parts acailable for supra suspension and this one looks like it snould be a breeze to fit? and re.drilling the spindles for chevy boltpattern (or the fronts for yota so you could run drift style rims) isnt a biggie