Thin aluminum grips, mag well, steel guide rod, base pads, and Grams mag guts (FSK 9-11 works). If you are adventuresome, machine (or Dremel) the forged checking off frame. Shooting factory ball at 180++ power factor the TS is a great setup with only those changes.
Running handloads at 168 to 172 PF you may want to entertain some serious efforts to reduce the weight of the frame. That is really a subjective call however...