I've been looking at the throwout bearing and slider/carrier..
The old one is on the right in both pictures..


You will notice that the return spring fastens in different places on the two carriers, and the section where the bearing rides is larger/taller on the old carrier.
Is there any reason for this? Should I use one over the other?
The old one is really a better fit on the front bearing retainer....and there is no good reason to not use it that I can see.