VPI HW-19 Mk. III upgrade question

I have a VPI HW-19 Mk. III, with PLC and Audioquest PT-8.  My question
is about the moving target upgrade to Mk. IV.  Since the latest
upgrade kit includes the lighter weight Aries Black Knight platter and
the inverted bearing, is this better than the old TNT platter upgrade
or just different?  Should I look for an old kit or go with the new
one?  Thanks very much.