Going from Thorens TD145 MKii to Rega/Music Hall?

I wonder how much would be an upgrade from TD145 MKii (or TD150/160/165/166) to Rega Planar 3 or Music Hall MF 5?
Having a better cartridge would be a better investment? I've used Grado Gold and AT125LC on my TD145 MKii (with Isotrack TP16 tonearm and TP62 arm wand).
For what's it worth - I went from a TD160 with grado platinum cartridge to a Rega P25 with Dynavector DV 20X H and it was a significant improvement. The improvement left me feeling no need to keep on the upgrade rollercoaster. The Rega/Dynavector is very satisfying and involving combination.
The TD160 was correspondingly better than the MMF5 which it replaced.
Hmm... TD160 with grado platinum was correspondigly better than MMF5 with Goldring 1012GX?
Would it be also due to Grado vs Goldring?