I'm in the process of sprucing up my 4th gen 3sgte to drop into my '91 turbo. From everything I've seen around the internet, the ct15 is a really fun turbo but it tends to have a harder time keeping up higher in the rev range. I know that this issue has been discussed at length on the interwebs but a lot of the threads that I am finding are a little bit outdated. From the places where i've seen real dyno numbers thrown out, it looks like the prime modified ct15's have the best output, however they do not provide that service any longer. It sort of appears to me that the prime guys would actually modify the exhaust side of the turbo as well as the compressor side. Does anyone else do that or am I mistaken? I have also seen some mentions on various threads about these modified ct's not always lasting very long. Does anyone have any experience with this? Anyone have any experiences that would be helpful in deciding which shop would be best to go through?