Why would a certain type of clutch blow your tranny? I think you should've left the first clutch in there, you would've been fine.
As to why the new one is slipping; when you installed it, did you have the flywheel resurfaced? If not, then that is probably why. It would also explain the chatter.
Here are the details on my clutch problem, and the reasons for the failure. There are also details on what clutch I went with, and on the lightweight flywheel I installed while I was at it. This might help to answer some of your questions.
http://www.rx7club.com/showthread.php?t=867870
.