Thorens TD-125 mkii - a significant improvement over the TD-160?

Hmmm... I never replaced an arm myself though I know many people do often. If you trust the TD-125 with SME arm is in as good condition as your current turntable, and the price is right, then that could be a simpler move. I just prefer the TD-160 for simplicity, visual and mechanical, and never felt I degraded my sound when I traded in my TD-125. Both of mine came refurbished from Vinyl Nirvana so I believe they both were performing as well as could be expected.

If you are curious you can likely research the ease of DIY swapping tonearms at Vinyl Engine and judge whether you want to take it on.

iirc, the weak point is the tp-16 arm. On many of those circular metal ring type mounts for the arm bearings, the given metals relax over time and get out of round. Depending on the design the bearings can and usually do tighten or loosen up.

the removable wand is a weak point, both electrically and mechanically. oops, wring arm, I think. regardless, removable head shells are a weak point.

Upgrading the arm can be one of the ways to go.

However beware arm mass and effective length of the given chosen replacement. It must fit in for the original in a fairly narrow range of mass and effective length.

the length issue is due to the arm base/board being very small, and no option for mounting outside of that small footprint is really viable.. and the mass being an issue as the suspension of the td-160 was not really designed to be messed with due to different arms in use.

Thank you both for your input!  I think I will stay put with the TD-160 and probably keep the TP-16 for now.  My phono stage is designed only for moving coil cartridges, but maybe I can consider stepping up my cartridge when the time is ripe.