they just reverse engineer the parts. & if you make a copy it doesnt come out quite right, but the quailty will improve maybe over the next 5-10 years but then will the price...
Frost. you are correct they would be good if they made them out of the same material etc.. but they dont. the material they use for the bearings & thrusts are not the same.
i have had a turbo X-Rayed as well. infact the Airport staff asked what it was & if they can scan it again... it was an 3.1 isuzu turbo.

i can post up losts of suituations that people have brought the copy turbos only to have them fail & then buy genuine turbos and have no problems..
if i personaly wanted to upgrade turbo on the MR2.. it wouldnt be nothing but a quailty turbocharger that i know inside & out.
Chris.