@boxer12 Let me quote our member Frogman to answer your question, see below:
The Grado XTZ was intended to be a more refined sounding version of the TLZ. I owned both (as well as the 8MZ) years ago. Both are fine cartridges, but while the XTZwas indeed a bit more refined sounding, it was also more polite sounding. The TLZ was noticeably more alive and dynamic sounding while sounding a bit brighter and very slightly unrefined by comparison. In my system at that time the TLZ was a better choice. Output for both was 1.5 mv vs 5 mv for the 8 series. If memory serves, the only difference between the TLZ and XTZ was a better dampened cantilever for the XTZwhich, contrary to the "rigidity at all costs" school of thought, was comprised of different sections of tube of different diameters to create the taper of the tube. Again, if memory serves, the XTZ's cantilever was made up of three different sections vs the TLZ's two. Both had excellent sound staging, fine generous bass, and very natural timbre (especially the XTZ).