Short of powder coating the metal bits on my TFTC, I think it's pretty well done and plays great.
What have I done ...
rebuilt the flippers
new flipper buttons
superband rubbers
100% LED's and LED Flashers
New drop target decals
cliffy protector
Purple scoop light mod
placed a blue led strip under the headbox to illuminate the rear PF based upon play mode
slingshot protectors
red dmd cover
chrome headbox trim
chrome leg bolts
mirror blades
new balls
re-chromed ramps
mylar protection for ball drops and kickout
and finally, a playfield so polished that an ant couldn't climb it